Transmission and Transfer Case — part 5 of 6 — 1998 Jeep Grand Cherokee ZJ Export Service Manual
Pages 1616–1676 · 60 pages · 8 words repaired
YOKE AND RANGE LEVER REMOVAL
(1) Remove front yoke nut:
(a) Move range lever to 4L position. (b) Remove nut with socket and impact wrench (Fig. 20).
(2) Remove yoke. If yoke is difficult to remove by hand, remove it with bearing splitter, or with standard two jaw puller (Fig. 21). Be sure puller tool is positioned on yoke and not on slinger as slinger will be damaged.
(3) Remove seal washer from front output shaft. Discard washer as it should not be reused.
(4) Remove nut and washer that attach range lever to sector shaft. Then move sector to neutral position and remove range lever from shaft (Fig. 22).
FRONT OUTPUT SHAFT AND DRIVE CHAIN REMOVAL
(1) Remove drive sprocket snap-ring (Fig. 23). (2) Remove drive sprocket and chain (Fig. 24). (3) Remove front output shaft (Fig. 25).
SHIFT FORKS AND MAINSHAFT REMOVAL AND DISASSEMBLY
(1) Remove shift detent plug, spring and pin (Fig. 26).
(2) Remove seal plug from low range fork lockpin access hole. Then move shift sector to align low range fork lockpin with access hole.
(3) Remove range fork lockpin with size number one easy-out tool as follows:
(a) Insert easy-out tool through access hole in side of transfer case and into lock-pin.
(b) Tap easy-out tool into lock-pin with hammer until tool is securely engaged into the lock-pin.
(c) Install a t-handle, such as from a tap and die set, onto the easy-out tool.
(d) Securely tighten the t-handle onto the tool. (e) In one motion, pull upward and turn the t-handle counter-clockwise to remove the lock-pin. (4) Remove shift rail by pulling it straight up and out of fork (Fig. 27).
(5) Remove mode fork and mainshaft as assembly (Fig. 28).
(6) Remove mode shift sleeve and mode fork assembly from mainshaft (Fig. 29). Note position of mode sleeve in fork and remove sleeve.
(7) Remove intermediate clutch shaft snap-ring (Fig. 30).
(8) Remove clutch shaft thrust ring (Fig. 31). (9) Remove intermediate clutch shaft (Fig. 32).
Removal
(10) Remove differential snap-ring (Fig. 33). (11) Remove differential (Fig. 34). (12) Remove differential needle bearings and both needle bearing thrust washers from mainshaft.
(13) Slide low range fork pin out of shift sector slot (Fig. 35).
(14) Remove low range fork and hub (Fig. 36). (15) Remove shift sector (Fig. 37).
(16) Remove shift sector bushing and O-ring (Fig. 38).
INPUT GEAR/LOW RANGE ASSEMBLY REMOVAL AND DISASSEMBLY
(1) Remove front bearing retainer bolts. (2) Remove front bearing retainer. Carefully pry retainer loose with screwdriver (Fig. 39). Position screwdriver in slots cast into retainer.
(3) Remove input gear snap-ring (Fig. 40).
(4) Remove input/low range gear assembly from bearing with Tool Handle C-4171 and Tool 7829A (Fig. 41).
(5) Remove low range gear snap-ring (Fig. 42). (6) Remove input gear retainer, thrust washers and input gear from low range gear (Fig. 43).
Removal
Installation
(7) Inspect low range annulus gear (Fig. 44). Gear is not a serviceable component. If damaged, replace gear and front case as assembly.
(8) Remove oil seals from following components: • front bearing retainer. • rear retainer. • oil pump. • case halves.
DIFFERENTIAL DISASSEMBLY
(1) Mark differential case halves for reference. (2) Remove differential case bolts. (3) Invert differential on workbench. (4) Separate top case from bottom case. Use slots in case halves to pry them apart (Fig. 45). (5) Remove thrust washers and planet gears from case pins (Fig. 46).
(6) Remove mainshaft and sprocket gears from bottom case (Fig. 47). Note gear position for reference before separating them.
ASSEMBLY
Lubricate transfer case components with automatic transmission fluid or petroleum jelly (where indicated) during assembly.
CAUTION: The bearing bores in various transfer case components contain oil feed holes. Make sure replacement bearings do not block the holes.
BEARING AND SEAL INSTALLATION
(1) Remove snap-ring that retains front output shaft front bearing in case (Fig. 48). Then remove bearing. Use hammer handle, or hammer and brass punch to tap bearing out of case.
(2) Install new front output shaft front bearing with Tool Handle C-4171 and Installer 8033A with the tapered cone upward (Fig. 49).
Removal
(3) Install front bearing snap-ring (Fig. 48). (4) Remove front output shaft seal using an appropriate pry tool (Fig. 50) or slide-hammer mounted screw.
(5) Install new front output shaft oil seal with Installer 6952-A (Fig. 51).
(6) Remove input gear bearing with Tool Handle C-4171 and Remover C-4210 (Fig. 52).
(7) Install snap-ring on new input gear bearing. (8) Install new input gear bearing with Tool Handle C-4171 and Remover C-4210. Install bearing far enough to seat snap-ring against case (Fig. 53).
(9) Remove the input gear pilot bearing by inserting a suitably sized drift into the splined end of the input gear and driving the bearing out with the drift and a hammer (Fig. 54).
(10) Install new pilot bearing with Installer 8128 and Handle C-4171 (Fig. 55).
(11) Install new seal in front bearing retainer with Installer 7884 (Fig. 56).
(12) Remove output shaft rear bearing with the screw and jaws from Remover L-4454 and Cup 8148 (Fig. 57).
(13) Install new bearing with Tool Handle C-4171 and Installer 5066 (Fig. 58). Lubricate bearing after installation.
(14) Install new seal in oil pump feed housing with Special Tool 7888 (Fig. 59).
(15) Install new pickup tube O-ring in oil pump (Fig. 60).
DIFFERENTIAL ASSEMBLY
(1) Lubricate differential components with automatic transmission fluid.
(2) Install sprocket gear in differential bottom case (Fig. 61).
(3) Install differential planet gears and new thrust washers (Fig. 62). Be sure thrust washers are installed at top and bottom of each planet gear. (4) Install differential mainshaft gear (Fig. 62). (5) Align and position differential top case on bottom case (Fig. 63). Align using scribe marks made at disassembly.
(6) While holding differential case halves together, invert the differential and start the differential case bolts.
(7) Tighten differential case bolts to specified torque.
INPUT GEAR/LOW RANGE ASSEMBLY
(1) Assemble low range gear, input gear thrust washers, input gear and input gear retainer (Fig. 64).
(2) Install low range gear snap ring (Fig. 65).
(3) Lubricate input gear and low range gears with automatic transmission fluid.
(4) Start input gear shaft into front case bearing.
(5) Press input gear shaft into front bearing. (6) Install new input gear snap ring (Fig. 66).
(7) Apply 3 mm (1/8 in.) wide bead of Mopart gasket maker or silicone adhesive sealer to seal surface of front bearing retainer.
(8) Install front bearing retainer (Fig. 67). Tighten retainer bolts to 16 ft. lbs. (21 N·m) torque.
SHIFT FORKS AND MAINSHAFT INSTALLATION
(1) Install new sector shaft O-ring and bushing (Fig. 68).
(2) Install shift sector. (3) Install new pads on low range fork, if necessary, (Fig. 69).
(4) Assemble low range fork and hub (Fig. 69). (5) Position low range fork and hub in case. Be sure low range fork pin is engaged in shift sector slot (Fig. 70).
(6) Install first mainshaft bearing spacer on mainshaft (Fig. 71).
(7) Install bearing rollers on mainshaft (Fig. 71). Coat bearing rollers with generous quantity of petroleum jelly to hold them in place.
(8) Install remaining bearing spacer on mainshaft (Fig. 71). Do not displace any bearings while installing spacer.
Spacers
(9) Install differential (Fig. 72). Do not displace mainshaft bearings when installing differential.
(10) Install differential snap-ring (Fig. 73). (11) Install intermediate clutch shaft (Fig. 74).
(12) Install clutch shaft thrust washer (Fig. 75). (13) Install clutch shaft snap-ring (Fig. 76).
(14) Inspect mode fork assembly (Fig. 77). Replace pads and bushing if necessary. Replace fork tube if bushings inside tube are worn or damaged. Also check springs and slider bracket (Fig. 77). Replace worn, damaged components.
(15) Install mode sleeve in mode fork (Fig. 78). Then install assembled sleeve and fork on mainshaft. Be sure mode sleeve splines are engaged in differential splines.
(16) Install mode fork and mainshaft assembly in case (Fig. 79). Rotate mainshaft slightly to engage shaft with low range gears.
(17) Rotate mode fork pin into shift sector slot. (18) Install shift rail (Fig. 80). Be sure rail is seated in both shift forks.
Installation
(19) Rotate shift sector to align lockpin hole in low range fork with access hole in case.
(20) Insert an easy-out in range fork lockpin to hold it securely for installation (Fig. 81). Lockpin is slightly tapered on one end. Insert tapered end into fork and rail. (21) Insert lockpin through access hole and into shift fork (Fig. 81). Then remove easy-out and seat the pin with pin punch.
(22) Install plug in lockpin access hole. (23) Install detent plunger, detent spring and detent plug in case (Fig. 82).
FRONT OUTPUT SHAFT AND DRIVE CHAIN INSTALLATION
(1) Install front output shaft (Fig. 83). (2) Install drive chain (Fig. 83). Engage chain with front output shaft sprocket teeth.
(3) Install drive sprocket (Fig. 83). Engage drive sprocket teeth with chain. Then engage sprocket splines with mainshaft splines
(4) Install drive sprocket snap-ring (Fig. 84)..
OIL PUMP AND REAR CASE INSTALLATION
(1) Insert oil pickup tube in oil pump and attach oil screen and connector hose to pickup tube. Then
install assembled pump, tube and screen in rear case (Fig. 85). Be sure screen is seated in case slot as shown.
(2) Install magnet in front case pocket (Fig. 86).
(3) Apply 3 mm (1/8 in.) wide bead of Mopar gasket maker or silicone adhesive sealer to seal surface of front case.
(4) Align and install rear case on front case. Be sure case locating dowels are in place and that mainshaft splines are engaged in oil pump inner gear.
(5) Install and tighten front case-to-rear case bolts to 41 N·m (30 ft. lbs.) torque. Be sure to install a washer under each bolt used at case dowel locations.
REAR RETAINER INSTALLATION
(1) Remove rear bearing in retainer using Installer 8128 and Handle C-4171.
(2) Install rear bearing in retainer with Tools C-4171 and 5064 (Fig. 87).
(3) Install rear bearing O.D. retaining ring with snap-ring pliers (Fig. 88). Be sure retaining ring is fully seated in retainer groove.
(4) Apply bead of Mopart Sealer P/N 82300234, or Loctitey Ultra Gray, to mating surface of rear retainer. Sealer bead should be a maximum of 3/16 in. (5) Install rear retainer on rear case. Tighten retainer bolts to 20–27 N·m (15–20 ft. lbs.) torque.
(6) Install rear bearing I.D. retaining ring and spacer on output shaft.
(7) Apply liberal quantity of petroleum jelly to new rear seal and to output shaft. Petroleum jelly is needed to protect seal lips during installation.
(8) Slide seal onto Seal Protector 6992 (Fig. 89). Slide seal protector and seal onto output shaft.
(9) Slide Installer C-4076-B onto seal protector with the recessed side of the tool toward the seal. Drive seal into rear bearing retainer with installer C-4076-B and handle MD-998323 (Fig. 90).
(10) Install rear slinger with installer C-4076-A and handle MD-998323 (Fig. 90).
(11) Install boot on output shaft slinger and crimp retaining clamp with tool C-4975-A (Fig. 91).
FRONT YOKE AND SWITCH INSTALLATION
(1) Install indicator switch in front case. Tighten switch to 20–34 N·m (15–25 ft. lbs.) torque.
(2) Lubricate yoke hub with transmission fluid and install yoke on front shaft.
(3) Install new seal washer on front shaft. (4) Install yoke on front shaft. Secure yoke with new nut.
CLEANING AND INSPECTION
NV242 TRANSFER CASE
Clean the transfer case parts with a standard parts cleaning solvent. Remove all traces of sealer from the cases and retainers with a scraper and all purpose cleaner. Use compressed air to remove solvent residue from oil feed passages in the case halves, retainers, gears, and shafts.
The oil pickup screen can be cleaned with solvent. Shake excess solvent from the screen after cleaning and allow it to air dry. Do not use compressed air.
MAINSHAFT/SPROCKET/HUB INSPECTION
Inspect the splines on the hub and shaft and the teeth on the sprocket. Minor nicks and scratches can be smoothed with an oilstone. However, replace any part is damaged.
Check the contact surfaces in the sprocket bore and on the mainshaft. Minor nicks and scratches can be smoothed with 320–400 grit emery cloth but do not try to salvage the shaft if nicks or wear is severe.
INPUT GEAR AND PLANETARY CARRIER
Check the teeth on the gear (Fig. 92). Minor nicks can be dressed off with an oilstone but replace the gear if any teeth are broken, cracked, or chipped. The bearing surface on the gear can be smoothed with 300–400 grit emery cloth if necessary.
Examine the carrier body and pinion gears for wear or damage. The carrier will have to be replaced as an assembly if the body, pinion pins, or pinion gears are damaged.
Check the lock ring and both thrust washers for wear or cracks. Replace them if necessary. Also replace the lock retaining ring if bent, distorted, or broken.
SHIFT FORKS/HUBS/SLEEVES
Check condition of the shift forks and mode fork shift rail (Fig. 93). Minor nicks on the shift rail can be smoothed with 320–400 grit emery cloth.
Inspect the shift fork wear pads. The mode fork pads are serviceable and can be replaced if necessary. The range fork pads are also serviceable.
Check both of the sleeves for wear or damage, especially on the interior teeth. Replace the sleeves if wear or damage is evident.
BOOT
Inspect the retainer components (Fig. 94). Replace the bearing if rough or noisy. Check the retainer for cracks or wear in the bearing bore. Clean the retainer sealing surfaces with a scraper and all purpose cleaner. This will ensure proper adhesion of the sealer during reassembly.
Replace the slinger and seal outright; do not reuse either part.
Inspect the retaining rings and washers. Replace any part if distorted, bent, or broken. Reuse is not recommended. Also replace the boot if cut or torn. Replace the boot band clamps, do not reuse them.
REAR OUTPUT SHAFT/YOKE/DRIVE CHAIN
Check condition of the seal contact surfaces of the yoke slinger (Fig. 95). This surface must be clean and smooth to ensure proper seal life. Replace the yoke nut and seal washer as neither part should be reused.
Inspect the shaft threads, sprocket teeth, and bearing surfaces. Minor nicks on the teeth can be smoothed with an oilstone. Use 320–400 grit emery to smooth minor scratches on the shaft bearing surfaces. Rough threads on the shaft can be chased if necessary. Replace the shaft if the threads are damaged, bearing surfaces are scored, or if any sprocket teeth are cracked or broken.
Examine the drive chain and shaft bearings. Replace the chain and both sprockets if the chain is stretched, distorted, or if any of the links bind. Replace the bearings if rough, or noisy.
LOW RANGE ANNULUS GEAR
Inspect annulus gear condition carefully. The gear is only serviced as part of the front case. If the gear is damaged, it will be necessary to replace the gear and front case as an assembly. Do not attempt to remove the gear (Fig. 96).
FRONT-REAR CASES AND FRONT RETAINER
Inspect the cases and retainer for wear and damage. Clean the sealing surfaces with a scraper and all purpose cleaner. This will ensure proper sealer adhesion at assembly. Replace the input retainer seal; do not reuse it.
Check case condition. If leaks were a problem, look for gouges and severe scoring of case sealing surfaces. Also make sure the front case mounting studs are in good condition.
Check the front case mounting studs and vent tube. The tube can be secured with Loctitey 271 or 680 if loose. The stud threads can be cleaned up with a die if necessary. Also check condition of the fill/ drain plug threads in the rear case. The threads can be repaired with a thread chaser or tap if necessary. Or the threads can be repaired with Helicoil stainless steel inserts if required.
OIL PUMP/OIL PICKUP
Examine the oil pump pickup parts. Replace the pump if any part appears to be worn or damaged. Do not disassemble the pump as individual parts are not available. The pump is only available as a complete assembly. The pickup screen, hose, and tube are the only serviceable parts and are available separately.
ADJUSTMENTS
SHIFT LINKAGE ADJUSTMENT
(1) Shift transfer case into 4L position. (2) Raise vehicle. (3) Loosen lock bolt on adjusting trunnion (Fig. 97).
(4) Be sure linkage rod slides freely in trunnion. Clean rod and apply spray lube if necessary.
(5) Verify that transfer case range lever is fully engaged in 4L position.
(6) Tighten adjusting trunnion lock bolt. (7) Lower vehicle.
SPECIFICATIONS
TORQUE
DESCRIPTION TORQUE Plug, Detent . . . . . . . . . . .16–24 N·m (12–18 ft. lbs.) Bolt, Diff. Case . . . . . . . . .17–27 N·m (15–24 ft. lbs.) Plug, Drain/Fill . . . . . . . . .20–25 N·m (15–25 ft. lbs.) Bolt, Front Brg. Retainer. .16–27 N·m (12–20 ft. lbs.) Bolt, Case Half . . . . . . . . .35–46 N·m (26–34 ft. lbs.) Nut, Front Yoke . . . . . .122–176 N·m (90–130 ft. lbs.) Screw, Oil Pump . . . . . . .1.2–1.8 N·m (12–15 in. lbs.) Nut, Range Lever . . . . . . .27–34 N·m (20–25 ft. lbs.) Bolt, Rear Retainer . . . . . .35–46 N·m (26–34 ft. lbs.) Nuts, Mounting. . . . . . . . . . . . . . .35 N·m (26 ft. lbs.) Bolts, U-Joint . . . . . . . . . . . . . . . .19 N·m (17 ft. lbs.)
SPECIAL TOOLS
SPECIAL TOOLS—NV242
GENERAL INFORMATION
GENERAL INFORMATION . . . . . . . . . . . . . . . . 271 RECOMMENDED LUBRICANT AND
FILL LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . 272 TRANSFER CASE IDENTIFICATION . . . . . . . . . 271 DIAGNOSIS AND TESTING
NV249 DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . 272 REMOVAL AND INSTALLATION
FRONT OUTPUT SHAFT SEAL . . . . . . . . . . . . 274 REAR RETAINER BUSHING AND SEAL . . . . . . 275 SHIFT LEVER . . . . . . . . . . . . . . . . . . . . . . . . . . 273 SPEEDOMETER . . . . . . . . . . . . . . . . . . . . . . . . 273
GENERAL INFORMATION
GENERAL INFORMATION
The NV249 (Fig. 1) is an on-demand 4-wheel drive transfer case with two operating ranges and a neutral position.
Operating ranges are 4-high and 4-low. The 4-low range is used for extra pulling power in off-road situations.
Engine torque is distributed to the front and rear axles through a viscous coupling. Nearly all the available engine torque is directed to the rear wheels during normal driving situations. when slippery conditions are encountered, the variable viscous directs torque to the front wheels as necessary. The NV249 low range is provided by a gear reduction system for
NV249 TRANSFER CASE
INDEX
page page
TRANSFER CASE . . . . . . . . . . . . . . . . . . . . . . 273 DISASSEMBLY AND ASSEMBLY
NV249 TRANSFER CASE . . . . . . . . . . . . . . . . . 276 CLEANING AND INSPECTION
NV249 COMPONENTS . . . . . . . . . . . . . . . . . . . 291 ADJUSTMENTS
SHIFT LINKAGE ADJUSTMENT . . . . . . . . . . . . 293 SPECIFICATIONS
TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 SPECIAL TOOLS
NV249 TRANSFER CASE . . . . . . . . . . . . . . . . . 294 increased low speed, off-road torque capability. This range is designed for temporary use only.
Transfer case operating ranges are selected with a floor mounted shift lever. The shift lever is connected to the transfer case range lever by an adjustable linkage rod. Range positions are marked on the shifter bezel plate.
TRANSFER CASE IDENTIFICATION
A circular I.D. tag is attached to the rear case of each NV249 transfer case (Fig. 2). The tag provides the transfer case model number, assembly number, serial number and low range ratio.
The transfer case serial number also represents the date of build.
RECOMMENDED LUBRICANT AND FILL LEVEL
Mopart Dexron II, or ATF Plus are the only lubricants recommended for the NV249 transfer case. Approximate fluid refill capacity is approximately 1.18 liters (2.50 pints).
The fill and drain plugs are both in the rear case. Correct fill level is to the bottom edge of the fill plug
DIAGNOSIS AND TESTING
NV249 DIAGNOSIS
hole. Be sure that the vehicle is level to ensure an accurate fluid level check.
TRANSFER CASE (a) Vehicle speed too great to permit (a) Stop vehicle and shift into desired
DIFFICULT TO SHIFT shifting. range. Or reduce speed to 3-4 km/h
OR WILL NOT SHIFT (2-3 mph) before attempting to shift.
INTO DESIRED (b) Stop vehicle, shift transmission to
RANGE {b) If vehicle was operated for extended neutral, shift transfer case to 2H mode
period in 4H mode on dry paved and operate vehicle on 2H on dry
surface, driveline torque load may paved surface.
cause difficulty. (c) Lubricate, repair or replace linkage, or
(c) Transfer case external shift linkage tighten loosen components as necessary.
binding. (d) Drain and refill to edge of fill hole with
ici . lubri MOPAR ATF PLUS (Type 7176) or
(d) Insufficient or incorrect lubricant. DEXRON II Automatic Transmission
Fluid.
(e) Disassemble unit and replace worn or
(e) Internal components binding, worn or damaged components as necessary.
damaged.
TRANSFER CASE (a) Insufficient or incorrect lubricant. (a) Drain and refill to edge of fill hole with
NOISY IN ALL MOPAR ATF PLUS (Type 7176) or
DRIVE MODES DEXRON II Automatic Transmission
Fluid. Check for leaks and repair if
necessary. If unit is still noisy after
drain and refill, disassembly and
inspection may be required to locate
source of noise.
(a} Stop vehicle, shift transfer case to
NOISY IN—OR (a) Transfer case not completely engaged Neutral, then shift back into 4L position.
OE TOT IVE in 4L position. (b) Tighten, lubricate, or repair linkage as
- - necessary.
LOW RANGE (b) Shift linkage loose or binding. (c} unit and repair as
. necessary
R fork cracked, inserts worn, or : . .
era on shift cel (d) Disassemble unit and repair as
(d) Annulus gear or lockplate work or Y
damaged. (a) Drain to correct level.
LUBRICANT (a) Transfer case overfilled. (b) Clear or replace vent if necessary.
cies store (b) Vent closed or restricted. (c} Replace seals. Be sure seal lip faces
(c) Output shaft seals damaged or interior of case when installed. Also be
SEALS OR FROM installed correctly. sure yoke seal surfaces are not scored
VENT or nicked. Remove scores and nicks with
fine sandpaper or replace yoke(s) if
necessary.
(a) Operate in 2H on hard surface (paved)
ABNORMAL (a) Extended operation on dry hard roads.
TIRE WEAR surface (paved) roads in 4H range.
J9021-152
REMOVAL AND INSTALLATION
TRANSFER CASE
REMOVAL
(1) Shift transfer case into Neutral. (2) Raise vehicle. (3) Drain transfer case lubricant. (4) Mark front and rear propeller shaft yokes for alignment reference.
(5) Support transmission with jack stand. (6) Remove rear crossmember, or skid plate. (7) Disconnect front/rear propeller shafts at transfer case.
(8) Disconnect vehicle speed sensor wires. (9) Disconnect transfer case linkage rod from range lever.
(10) Disconnect transfer case vent hose (Fig. 3) and indicator switch harness, if necessary.
(11) Support transfer case with transmission jack. (12) Secure transfer case to jack with chains. (13) Remove nuts attaching transfer case to transmission.
(14) Pull transfer case and jack rearward to disengage transfer case.
(15) Remove transfer case from under vehicle.
INSTALLATION
(1) Mount transfer case on a transmission jack. (2) Secure transfer case to jack with chains. (3) Position transfer case under vehicle. (4) Align transfer case and transmission shafts and install transfer case on transmission.
(5) Install and tighten transfer case attaching nuts to 35 N·m (26 ft. lbs.) torque (Fig. 3).
(6) Connect vehicle speed sensor wires, and vent hose.
(7) Connect indicator switch harness to transfer case switch, if necessary. Secure wire harness to clips on transfer case.
(8) Align and connect propeller shafts. Refer to Group 3, Differential and Driveline, for proper procedures and specifications.
(9) Fill transfer case with correct fluid. Check transmission fluid level. Correct as necessary.
(10) Install rear crossmember, or skid plate. Tighten crossmember bolts to 41 N·m (30 ft. lbs.) torque.
(11) Remove transmission jack and support stand. (12) Connect shift rod to transfer case range lever. (13) Adjust transfer case shift linkage. (14) Lower vehicle and verify transfer case shift operation.
SHIFT LEVER
REMOVAL
(1) Shift transfer case into 4L. (2) Raise vehicle. (3) Loosen adjusting trunnion locknut and slide shift rod out of trunnion (Fig. 4). If rod lacks enough travel to come out of trunnion, push trunnion out of torque shaft.
(4) Lower vehicle. (5) Remove console. Refer to Group 23, Body, for proper procedures.
(6) Remove screws attaching lever assembly to floorpan and remove assembly and shift rod (if left attached).
INSTALLATION
(1) If shift rod was not removed from lever assembly, work rod down through floorpan opening. Then position lever assembly on floorpan and install assembly attaching screws.
(2) Install console. Refer to Group 23, Body, for proper procedures.
(3) Raise vehicle. (4) Connect trunnion to torque shaft arm. Or, slide shift rod into trunnion on range lever. Be sure shift rod slides freely in trunnion.
(5) Verify that range lever is in 4L position. Then tighten trunnion lock bolt.
(6) Lower vehicle and check transfer case shift operation.
SPEEDOMETER
REMOVAL
(1) Raise vehicle. (2) Disconnect wires from vehicle speed sensor. (3) Remove adapter clamp and screw (Fig. 5). (4) Remove speed sensor and speedometer adapter as an assembly.
(5) Remove speed sensor retaining screw and remove sensor from adapter.
(6) Remove speedometer pinion from adapter. Replace pinion if chipped, cracked, or worn.
(7) Inspect sensor and adapter O-rings (Fig. 5). Remove and discard O-rings if worn or damaged.
(8) Inspect terminal pins in speed sensor. Clean pins with Mopart electrical spray cleaner if dirty or oxidized. Replace sensor if faulty, or if pins are loose, severely corroded, or damaged.
INSTALLATION AND INDEXING
(1) Thoroughly clean adapter flange and adapter mounting surface in housing. Surfaces must be clean for proper adapter alignment and speedometer operation.
(2) Install new O-rings on speed sensor and speedometer adapter (Fig. 5), if necessary.
(3) Lubricate sensor and adapter O-rings with transmission fluid.
(4) Install vehicle speed sensor in speedometer adapter. Tighten sensor attaching screw to 2-3 N·m (15-27 in. lbs.) torque.
(5) Install speedometer pinion in adapter. (6) Count number of teeth on speedometer pinion. Do this before installing assembly in housing. Then lubricate pinion teeth with transmission fluid.
(7) Note index numbers on adapter body (Fig. 6). These numbers will correspond to number of teeth on pinion.
(8) Install speedometer assembly in housing. (9) Rotate adapter until required range numbers are at 6 o-clock position. Be sure range index numbers correspond to number of teeth on pinion gear.
(10) Install speedometer adapter clamp and retaining screw. Tighten clamp screw to 10-12 N·m (90-110 in. lbs.) torque. (11) Connect wires to vehicle speed sensor. (12) Lower vehicle and top off transmission fluid level if necessary.
FRONT OUTPUT SHAFT SEAL
REMOVAL
(1) Raise vehicle. (2) Remove front propeller shaft. Refer to Group 3, Differential and Driveline, for proper procedure.
(3) Remove front output shaft yoke. (4) Remove seal from front case with pry tool (Fig. 7).
INSTALLATION
(1) Install new front output seal in front case with Installer Tool 6952-A as follows:
Adapter
(a) Place new seal on tool. Garter spring on seal goes toward interior of case.
(b) Start seal in bore with light taps from hammer (Fig. 8). Once seal is started, continue tapping seal into bore until installer tool seats against case.
REAR RETAINER BUSHING AND SEAL
REMOVAL
(1) Raise vehicle. (2) Remove rear propeller shaft. Refer to Group 3, Differential and Driveline, for proper procedure.
(3) Using a suitable pry tool or slide-hammer mounted screw, remove the rear retainer seal.
(4) Using Remover 6957, remove bushing from rear retainer (Fig. 9).
INSTALLATION
(1) Clean fluid residue from sealing surface and inspect for defects. (2) Position replacement bushing in rear retainer with fluid port in bushing aligned with slot in retainer.
(3) Using Installer 8145, drive bushing into retainer until installer seats against case (Fig. 10).
(4) Using Installer C-3995-A, install seal in rear retainer (Fig. 11).
(5) Install propeller shaft. (6) Verify proper fluid level. (7) Lower vehicle.
DISASSEMBLY AND ASSEMBLY
NV249 TRANSFER CASE
DISASSEMBLY
Position transfer case on shallow drain pan. Remove drain plug and drain lubricant remaining in case.
REAR RETAINER AND OIL PUMP REMOVAL
(1) Remove the speedometer adapter. (2) Remove rear retainer bolts (Fig. 12). (3) Remove rear bearing locating ring access cover screws, cover and gasket (Fig. 13).
Removal
(4) Loosen rear retainer with pry tool to break sealer bead. Pry only against retainer boss as shown (Fig. 14).
(5) Remove rear retainer as follows:
(a) Spread rear bearing locating ring with snap ring pliers (Fig. 15).
(b) Then slide retainer off mainshaft and rear bearing (Fig. 16).
(6) Remove speedometer drive gear (Fig. 17). (7) Remove rear bearing snap-ring. (8) Remove rear bearing. Note position of bearing locating ring groove for assembly reference.
(9) Disengage oil pickup tube from oil pump and remove oil pump assembly (Fig. 18).
(10) Remove pick-up tube o-ring from oil pump (Fig. 19), if necessary. Do not disassemble the oil pump, it is not serviceable.
VISCOUS COUPLER REMOVAL
(1) Remove oil pump locating snap-ring and viscous coupling snap-ring from mainshaft (Fig. 20).
(2) Remove viscous coupling from mainshaft (Fig. 20).
YOKE AND RANGE LEVER REMOVAL
(1) Remove transfer case indicator switch. (2) Remove front yoke nut as follows:
(a) Move range lever to 4L position.
(b) Remove nut with socket and impact wrench (Fig. 21). (3) Remove yoke. If yoke is difficult to remove by hand, remove it with bearing splitter, or with standard two jaw puller (Fig. 22). Be sure puller tool is positioned on yoke and not on slinger as slinger will be damaged.
(4) Remove seal washer from front output shaft. Discard washer as it should not be reused.
(5) Remove nut and washer that attach range lever to sector shaft. Then move sector to neutral position and remove range lever from shaft (Fig. 23).
FRONT OUTPUT SHAFT AND DRIVE CHAIN REMOVAL
(1) Support transfer case so rear case is facing upward.
(2) Remove bolts holding front case to rear case. The case alignment bolt require flat washers (Fig. 24).
(3) Loosen rear case with flat blade screwdriver to break sealer bead. Insert screwdriver blade only into notches provided at each end of case (Fig. 25).
(4) Remove rear case (Fig. 26).
(5) Remove oil pickup tube from rear case (Fig. 27).
(6) Remove drive gear snap-ring (Fig. 28). (7) Disengage drive gear (Fig. 28). Pry gear upward and off mainshaft as shown.
(8) Remove front output shaft, drive chain and drive gear as assembly (Fig. 28).
Removal
SHIFT FORKS AND MAINSHAFT REMOVAL
(1) Remove detent plug, O-ring, detent spring and detent plunger (Fig. 29).
(2) Remove mainshaft from clutch sleeve and input gear pilot bearing.
(3) Rotate shift sector so sector teeth face upward (Fig. 30).
(4) Remove range fork, rail and clutch sleeve as assembly (Fig. 31). Lift shift rail upward, rotate fork out of shift sector and remove assembly.
(5) Remove shift sector. Rotate and tilt sector as needed to remove it (Fig. 32).
(6) Remove shift sector bushing and O-ring (Fig. 33).
INPUT GEAR/LOW RANGE ASSEMBLY REMOVAL
(1) Turn front case on side so front bearing retainer is accessible.
(2) Remove front bearing retainer bolts (Fig. 34). (3) Remove front bearing retainer as follows:
(a) Loosen retainer with flat blade screwdriver to break sealer bead. To avoid damaging case and retainer, position screwdriver blade only in slots provided in retainer (Fig. 35). (b) Then remove retainer from case and gear.
(4) Remove snap-ring that retains input gear shaft in front bearing (Fig. 36). (5) Remove input and low range gear assembly (Fig. 37).
(6) Remove oil seals from following components: • front bearing retainer. • rear retainer. • case halves.
INPUT AND LOW RANGE GEAR DISASSEMBLY
(1) Remove snap-ring that retains input gear in low range gear (Fig. 38).
(2) Remove retainer (Fig. 39). (3) Remove front tabbed thrust washer (Fig. 40). (4) Remove input gear (Fig. 41).
Removal
(5) Remove rear tabbed thrust washer from low range gear (Fig. 42).
ASSEMBLY
Lubricate transfer case components with Mopart Dexron II automatic transmission fluid or petroleum jelly (where indicated) during assembly.
CAUTION: The bearing bores in various transfer case components contain oil feed holes. Make sure replacement bearings do not block the holes.
BEARING AND SEAL INSTALLATION
(1) Remove front output shaft seal from front case with pry tool (Fig. 43).
(2) Remove snap-ring that retains front output shaft bearing in front case (Fig. 44).
(3) Using tool 6953, remove bearing from front case (Fig. 45).
(4) Using tool 6953, install new bearing. (5) Install snap-ring to hold bearing into case. (6) Install new front output seal in front case with Installer Tool 6952-A as follows:
(a) Place new seal on tool. Garter spring on seal goes toward interior of case.
(b) Start seal in bore with light taps from hammer (Fig. 46). Once seal is started, continue tap-
Removal
ping seal into bore until installer tool bottoms against case.
(7) Remove the output shaft rear bearing with the screw and jaws from Remover L-4454 and Cup 8148 (Fig. 47).
(8) Install new bearing with Tool Handle C-4171 and Installer 5066 (Fig. 48). The bearing bore is chamfered at the top. Install the bearing so it is flush with the lower edge of this chamfer (Fig. 49).
(9) Using Remover C-4210 and Handle C-4171, drive input shaft bearing from inside the annulus gear opening in the case. (Fig. 50).
(10) Install locating ring on new bearing. (11) Position case so forward end is facing upward. (12) Using Remover C-4210 and Handle C-4171, drive input shaft bearing into case. The bearing locating ring must be fully seated against case surface (Fig. 51).
(13) Remove input gear pilot bearing by inserting a suitably sized drift into the splined end of the input gear and driving the bearing out with the drift and a hammer (Fig. 52).
(14) Install new pilot bearing with Installer 8128 and Handle C-4171 (Fig. 53).
(15) Remove front bearing retainer seal with suitable pry tool.
(16) Install new front bearing retainer with Installer 7884 (Fig. 54).
INPUT AND LOW RANGE GEAR ASSEMBLY
(1) Lubricate gears and thrust washers (Fig. 55) with recommended transmission fluid.
(2) Install first thrust washer in low range gear (Fig. 55). Be sure washer tabs are properly aligned in gear notches.
(3) Install input gear in low range gear. Be sure input gear is fully seated. (4) Install remaining thrust washer in low range gear and on top of input gear. Be sure washer tabs are properly aligned in gear notches.
(5) Install retainer on input gear and install snapring.
INPUT GEAR/LOW RANGE INSTALLATION
(1) Align and install low range/input gear assembly in front case (Fig. 56). Be sure low range gear pinions are engaged in annulus gear and that input gear shaft is fully seated in front bearing.
(2) Install snap-ring to hold input/low range gear into front bearing (Fig. 57).
(3) Clean gasket sealer residue from retainer and inspect retainer for cracks or other damage. (4) Apply a 3 mm (1/8 in.) bead of Mopart gasket maker or silicone adhesive to sealing surface of retainer.
(5) Align cavity in seal retainer with fluid return hole in front of case.
CAUTION: Do not block fluid return cavity on sealing surface of retainer when applying MoparT gasket maker or silicone adhesive sealer. Seal failure and fluid leak can result.
(6) Install bolts to hold retainer to transfer case (Fig. 58). Tighten to 21 N·m (16 ft. lbs.) of torque.
SHIFT FORKS AND MAINSHAFT INSTALLATION
(1) Install new sector shaft O-ring and bushing (Fig. 59).
(2) Install shift sector (Fig. 60).
(3) Install new pads on range fork (Fig. 61), if necessary.
(4) Install clutch sleeve in range fork (Fig. 61). (5) Install assembled range fork and clutch sleeve (Fig. 62).
(6) Insert range fork pin in sector. Then rotate sector and seat clutch gear in low range gear.
(7) Verify that range fork rail is seated in case bushing and that clutch sleeve is properly engaged in low range gear.
(8) Rotate sector to Neutral position.
(9) Install new O-ring on detent plug (Fig. 63). (10) Lubricate detent plunger with transmission fluid or light coat of petroleum jelly.
Install detent plunger, spring and plug (Fig. 63).
(11)
(12) Verify that plunger is properly engaged in sector.
(13) Insert mainshaft into input gear pilot bearing.
FRONT OUTPUT SHAFT AND DRIVE CHAIN INSTALLATION
(1)
Lubricate front output shaft-sprocket assembly, drive chain and drive sprocket with transmission fluid.
(2) Assemble drive chain, drive sprocket and front output shaft (Fig. 64).
(3) Start drive sprocket on mainshaft.
And Drive Sprocket
(4) Guide front shaft into bearing and drive sprocket onto mainshaft drive gear (Fig. 64).
(5) Install drive sprocket snap-ring (Fig. 65).
(6) Clean sealing flanges of front case and rear case with a wax and grease remover.
(7) Apply 3 mm (1/8 in.) wide bead of Mopart gasket maker or silicone adhesive sealer to mounting flange of front case. Work sealer bead around bolt holes as shown (Fig. 66).
(8) Install oil pickup tube in rear case. Be sure tube is seated in case notch as shown (Fig. 67).
(9) Install magnet in front case pocket (Fig. 68). (10) Align and install rear case on front case (Fig. 69).
(11) Verify that oil pickup tube is still seated in case notch and tube end is pointed toward mainshaft (Fig. 70).
(12) Install case attaching bolts. Alignment bolts at each end of case are only ones requiring washers (Fig. 71).
(13) Tighten case bolts to 27-34 N·m (20-25 ft. lbs.) torque.
YOKE AND RANGE LEVER INSTALLATION
(1) Install indicator switch in front case. Tighten switch to 20–34 N·m (15–25 ft. lbs.) torque.
(2) Install range lever, washer and locknut on sector shaft (Fig. 72). Tighten locknut to 27-34 N·m (20-25 ft. lbs.) torque.
(3) Install new seal washer on front output shaft (Fig. 74).
(4) Lubricate yoke hub with transmission fluid and install yoke on front shaft. (5) Install new seal washer on front shaft. (6) Install yoke and new yoke nut on front output shaft (Fig. 73).
(7) Tighten yoke nut to 122-176 N·m (90-130 ft. lbs.) torque. Use Tool C-3281, or similar tool to hold yoke while tightening yoke nut.
VISCOUS COUPLER
(1) Install coupling on mainshaft (Fig. 75).
(2) Install coupling retaining snap-ring first (Fig. 75). Be sure snap ring is fully seated before proceeding. (3) Install oil pump locating snap-ring on mainshaft (Fig. 75).
REAR RETAINER AND OIL PUMP INSTALLATION
(1) Install new O-ring on flanged end of oil pickup tube.
(2) Install oil pump (Fig. 76).
Installation
(3) Insert oil pickup tube in pump (Fig. 77). (4) Install rear bearing on mainshaft (Fig. 77). Locating ring groove in bearing goes toward end of mainshaft.
(5) Install rear bearing retaining snap-ring (Fig. 78).
(6) Install speedometer drive gear (Fig. 79). (7) Install rear bearing locating ring in rear retainer, if ring was removed during overhaul.
(8) Apply 3 mm (1/8 in.) wide bead of Mopart gasket maker or silicone adhesive sealer to mounting surface of rear retainer. Allow sealer to set-up slightly before proceeding.
(9) Slide rear retainer onto mainshaft (Fig. 80). (10) Spread rear bearing locating ring and slide rear retainer into place on rear case (Fig. 81).
(11) Install and tighten rear retainer bolts to 27-34 N·m (20-25 ft. lbs.).
(12) Install locating ring access cover and gasket (Fig. 82). Tighten plate attaching screws to 10 N·m (85 in. lbs.) torque.
Gasket
FINAL ASSEMBLY
(1) Install drain plug. Tighten plug to 41-54 N·m (30-40 ft. lbs.) torque.
(2) Level transfer case and fill it with Mopar Dexron II automatic transmission fluid. Correct fill level is to bottom edge of fill plug hole.
(3) Install and tighten fill plug to 41-54 N·m (30-40 ft. lbs.) torque.
CLEANING AND INSPECTION
NV249 COMPONENTS
GENERAL
Clean the transfer case components with parts cleaning solvent. Flush the oil passages in the cases and drivetrain components with solvent. This will help remove dirt and particles from these passages.
Dry the transfer case components with compressed air or allow them to air dry on clean shop towels.
Apply compressed air through all oil passages in the cases and gear components to clear them of any residue.
MAINSHAFT
Examine the mainshaft components carefully for evidence of wear or damage.
Replace the thrust washers if worn or damaged. Replace the mainshaft and sprocket gears if the teeth or gear bores are worn or damaged.
Replace the mainshaft bearings if worn, flat spotted, brinelled, or damaged in any way.
Replace the mainshaft if it exhibits wear or damage to the bearing surfaces, splines or gear teeth.
INPUT AND LOW RANGE GEARS
Inspect the low range gear pinions and pinion pins. Replace the low range gear if any of the pins or pinions are worn or damaged. Inspect the thrust washers, retainer, and snapring. Replace the snap-ring if bent, or distorted. Replace the thrust washers and retainer if worn, cracked or damaged in any way.
Examine the input gear carefully. Be sure the gear teeth and bearing surfaces are in good condition. Replace the gear if wear or damage is evident.
Check the input gear pilot bearing. Rotate the bearing and check for roughness or noise. Also check bearing position in the bore. The bearing should be recessed approximately 2.5 mm (0.100 in.) below the top edge of the bore. The bearing should not be seated at the bottom of the bore. Replace the bearing if worn, or roughness is evident. Replace both the gear and bearing if the bearing is a loose fit in the bore.
GEAR CASE AND RETAINERS
Examine both case halves and retainers carefully. Replace any retainer or case half if wear, cracks, or other damage is evident.
Check condition of the low range annulus gear and the shift rail bushing in the front case (Fig. 83). The low range annulus gear is not a serviceable part. Replace the gear and case as an assembly if the gear is loose, worn, or damaged. The shift rail bushing is a serviceable part and can be replaced if necessary.
Check the bushing in the rear retainer. Replace the bushing if worn or scored.
Examine the sealing surfaces of both case halves and retainers. Small burrs, or scratches on these surfaces can be reduced with crocus cloth or a fine tooth file.
Examine condition of the shift rail bushing in the front case. If the bushing is worn or damaged, it can be removed with a blind hole type puller. A replacement bushing can be installed with a suitable size
driver. Recess the bushing slightly below the edge of the bore but do not seat it all the into the case.
GEARTRAIN
Inspect the mainshaft splines, gear teeth and bearing surfaces carefully for evidence of wear, or damage. Replace the shaft if necessary. do not attempt to salvage it if damaged.
The shift rail and range fork are an assembly. Replace both parts if either is damaged. However, the nylon pads in the fork can be replaced if worn, or cracked.
Inspect the transfer case snap rings closely. Do not attempt to salvage a distorted snap ring by straightening or reshaping it. Replace any snap ring that is distorted, or worn.
Inspect the low range gear, input gear and the gear thrust washers retainer, and snap ring. The low range gear is serviced as an assembly only. Replace the gear if the case or pinions are damaged.
During inspection, also make sure the seal surface of the input gear is in good condition. Minor nicks on this surface can be reduced with crocus cloth. However, replace the gear if the seal surface is severely scored or worn.
The speedometer gear should be replaced if worn, cracked, or if the small spline teeth are worn.
OIL PUMP AND VISCOUS COUPLING
The oil pump and viscous coupling are not serviceable components. Replace the coupling as an assembly if it is leaking or damaged. Replace the oil pump as an assembly if the gear teeth are worn, or if the pump has become damaged.
BEARINGS AND SEALS
The transfer case seals should be replaced during overhaul. Use new seals in the input gear bearing retainer, front case and rear retainer. Also replace the yoke seal washer and the detent plug O-ring.
Check condition of each transfer case bearing. Replace any bearing exhibiting signs of roughness, wear, or damage.
ADJUSTMENTS
SHIFT LINKAGE ADJUSTMENT
(1) Shift transfer case into Neutral position. (2) Raise vehicle on hoist that will allow all four wheels to rotate freely.
(3) Loosen trunnion lock bolt (Fig. 84). Loosen bolt enough so selector rod slides freely in trunnion.
(4) Verify that shift lever on transfer case is in Neutral position.
(5) Tighten trunnion lock bolt to 11-20 N·m (96-180 in. lbs.) torque.
(6) Lower vehicle enough for entry into driver seat but keep all wheels off shop floor.
(7) Verify correct linkage adjustment. Start engine, shift transmission into gear and shift transfer case into all ranges. Be sure transfer case is fully engaged in high and low range. Readjust linkage if necessary. (8) Shut engine off and lower vehicle completely.
SPECIFICATIONS
TORQUE
DESCRIPTION TORQUE Bolt, crossmember . . . . . .41-47 N·m (30-35 ft. lbs.) Plug, Detent . . . . . . . . . . .16-24 N·m (12-18 ft. lbs.) Plugs, drain/fill. . . . . . . . .41-54 N·m (30-40 ft. lbs.) Switch, Electric . . . . . . . .20-34 N·m (15-25 ft. lbs.) Bolts, front brg.
retainer . . . . . . . . . . . . .16-24 N·m (12-18 ft. lbs.) Bolts, case half . . . . . . . . .27-34 N·m (20-25 ft. lbs.) Nut, output yoke . . . .122–176 N·m (90-130 ft. lbs.) Bolts, rear extension . . . .27-34 N·m (20-25 ft. lbs.) Lock-nut, shift . . . . . . . . .27-34 N·m (20-25 ft. lbs.) Bolt, shift rod . . . . . . . . .11-20 N·m (96-180 in. lbs.) Nuts, T-case mount stud . . . . . . . . . . . . . . . .33-41 N·m (24-30 ft. lbs.) Bolt, U-joint clamp. . . . . .16-22 N·m (12-16 ft. lbs.)
SPECIAL TOOLS
NV249 TRANSFER CASE
TRANSMISSION SHIFT PATTERN
The AX 15 shift pattern is shown in (Fig. 3). First and second and third and fourth gear ranges are in line for improved shifting. Fifth and reverse gear ranges are also in line at the extreme right of the pattern (Fig. 3).
The AX 15 is equipped with a reverse lockout mechanism. The shift lever must be moved through the Neutral detent before making a shift to reverse.
TRANSMISSION LUBRICANT
Recommended lubricant for AX 15 transmissions is Mopar 75W–90, API Grade GL–5 gear lubricant, or equivalent.
Correct lubricant level is from the bottom edge, to no more than 6 mm (1/4 in.) below the bottom edge of the fill plug hole.
Approximate dry fill lubricant capacity is: • 3.10 liters (3.27 qts.) in 4–wheel drive models
TRANSMISSION SWITCH AND PLUG LOCATIONS
The fill plug is at the driver side of the gear case (Fig. 4).
The drain plug and backup light switch are on the passenger side of the gear case (Fig. 5).
TRANSMISSION GEAR RATIOS
AX 15 gear ratios are:
First gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.83:1 Second gear . . . . . . . . . . . . . . . . . . . . . . . . . . 2.33:1 Third gear . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.44:1 Fourth gear . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00:1 Fifth gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.79:1 Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.22:1
TRANSMISSION ASSEMBLY INFORMATION
Lubricate the transmission components with gear lubricant during assembly. Use petroleum jelly to
lubricate seal lips and/or hold parts in place during installation.
DIAGNOSIS AND TESTING
LOW LUBRICANT LEVEL
A low transmission lubricant level is generally the result of a leak, inadequate lubricant fill, or an incorrect lubricant level check.
Leaks can occur at the mating surfaces of the gear case, intermediate plate and adapter or extension housing, or from the front/rear seals. A suspected leak could also be the result of an overfill condition.
Leaks at the rear of the extension or adapter housing will be from the housing oil seals. Leaks at component mating surfaces will usually be the result of inadequate sealer, gaps in the sealer, incorrect bolt tightening, or use of a non–recommended sealer.
A leak at the front of the transmission will be from either the front bearing retainer or retainer seal. Lubricant may be seen dripping from the clutch housing after extended operation. If the leak is severe, it may also contaminate the clutch disc causing slip, grab and chatter. Transmissions filled from air or electrically powered lubricant containers can be under filled. This generally happens when the container delivery mechanism is improperly calibrated. Always check the lubricant level after filling to avoid an under fill condition.
A correct lubricant level check can only be made when the vehicle is level; use a drive–on hoist to ensure this. Also allow the lubricant to settle for a minute or so before checking. These recommendations will ensure an accurate check and avoid an under–or–over fill condition.
HARD SHIFTING
Hard shifting is usually caused by a low lubricant level, improper or contaminated lubricants, component damage, incorrect clutch adjustment, or by a damaged clutch pressure plate or disc.
Substantial lubricant leaks can result in gear, shift rail, synchro and bearing damage. If a leak goes undetected for an extended period, the first indications of a problem are usually hard shifting and noise.
Incorrect or contaminated lubricants can also contribute to hard shifting. The consequence of using non–recommended lubricants is noise, excessive wear, internal bind and hard shifting.
Improper clutch release is a frequent cause of hard shifting. Incorrect adjustment or a worn, damaged pressure plate or disc can cause incorrect release. If the clutch problem is advanced, gear clash during shifts can result.
Worn or damaged synchro rings can cause gear clash when shifting into any forward gear. In some new or rebuilt transmissions, new synchro rings may tend to stick slightly causing hard or noisy shifts. In most cases, this condition will decline as the rings wear–in.
TRANSMISSION NOISE
Most manual transmissions make some noise during normal operation. Rotating gears can generate a mild whine that may only be audible at extreme speeds.
Severe, obviously audible transmission noise is generally the result of a lubricant problem. Insufficient, improper, or contaminated lubricant can promote rapid wear of gears, synchros, shift rails, forks and bearings. The overheating caused by a lubricant problem, can also lead to gear breakage.
REMOVAL AND INSTALLATION
TRANSMISSION
REMOVAL
1. Disconnect the battery negative cable. 2. Remove the shifter boot and shifter. 3. Raise the vehicle on a hoist. 4. Drain the transmission fluid (Fig. 6).
5. Support the engine and transmission with an adjustable jack stand.
6. Remove exhaust pipe and heat shield. 7. Mark the front and rear propeller shafts for installation alignment (Fig. 7).
8. Remove the front propeller shaft. 9. Remove the rear propeller shaft. 10. Remove the transmission skid plate.
11. Disconnect the transfer case linkage and vehicle speed sensor electrical connector and vent tube hose (Fig. 8).
12. Reposition the adjustable jackstand under the engine.
13. Place a transmission jack under the transmission and secure the transmission with safety chains.
14. Remove the rear transmission mount. 15. Remove the rear crossmember. 16. Remove the transfer case assembly. Refer to Transfer Case removal later in this Group.
17. Lower the engine and transmission no more than 7.6 cm.
18. Remove the two (2) upper and two (2) mid clutch housing to engine bolts.
19. Remove the engine speed sensor (crankshaft position sensor) (Fig. 9).
20. Remove the clutch slave cylinder from the clutch housing.
21. Remove the lower transmission bolts. 22. Remove the transmission assembly from the vehicle.
INSTALLATION
1. Mount the transmission on a transmission jack and secure the transmission with safety chains.
2. Install the transmission to the vehicle (Fig. 10). 3. Install the two (2) lower transmission bolts. Tighten the bolts to 74.6 N·m.
4. Install the clutch slave cylinder to the clutch housing.
5. Install the engine speed sensor (crankshaft position sensor) to the vehicle (Fig. 9).
6. Install the two (2) upper clutch housing to engine bolts. Tighten the bolts to 36.6 N·m.
7. Install the two (2) mid clutch housing to engine bolts. Tighten the bolts to 58.3 N·m.
8. Raise the engine and transmission with the adjustable jackstand.
9. Install the transfer case assembly. Refer to Transfer Case installation later in this Group.
10. Install the rear crossmember. 11. Install the rear transmission mount. 12. Connect the transfer case linkage and vehicle speed sensor electrical connector and vent tube (Fig. 8).
13. Install the transmission skid plate. 14. Align and install the front and rear propeller shafts.
15. Install the exhaust pipe and heat shield.
16. Remove the transmission jack. 17. Fill the transmission with the proper fluid (Fig. 12).
18. Remove the adjustable jackstand from under the engine.
19. Lower the vehicle from the hoist. 20. Install the shifter boot and shifter. 21. Reconnect the battery negative cable.
SPECIFICATIONS
TORQUE
DESCRIPTION TORQUE Clutch Housing to Engine
Top (2) Bolts . . . . . . . . . . . . 36.6 N·m (27 ft. lbs.) Clutch Housing to Engine
Mid-Point (2) Bolts . . . . . . . 58.3 N·m (43 ft. lbs.) Clutch Housing to Engine
Bottom (2) Bolts . . . . . . . . . . 74.6 N·m (55 ft. lbs.) Clutch Housing to Transmission bolts . . . . . . . . . . . . . . . . . . . 38.0 N·m (28 ft. lbs.) Transfer Case to Transmission
Attaching Nuts . . . . . . . . . . . . 35 N·m (26 ft. lbs.) Propeller Shaft Bolts . . . . . . . 26.5 N·m (19.5 ft. lbs.)
GENERAL INFORMATION
NV231 TRANSFER CASE
The NV231 is a part-time transfer case with a low range reduction gear system. The NV231 has three operating ranges plus a Neutral position. A low range system provides a reduction ratio for increased low speed torque capability.
The input gear is splined to the transmission output shaft. The input gear drives the mainshaft through the planetary assembly and range hub. The front output shaft is operated by a drive chain that connects the shaft to a drive sprocket on the mainshaft. The drive sprocket is engaged/disengaged by the mode fork, which operates the mode sleeve and hub. The sleeve and hub are not equipped with a synchronizer mechanism for shifting.
The geartrain is mounted in two aluminum case halves attached with bolts. The mainshaft front and rear bearings are mounted in aluminum retainer housings bolted to the case halves.
OPERATING RANGES
Transfer case operating ranges are: • 2WD (2-wheel drive) • 4x4 (4-wheel drive) • 4 Lo (4-wheel drive low range The 2WD range is for use on any road surface at any time.
The 4x4 and 4 Lo ranges are for off road use only. They are not for use on hard surface roads. The only exception being when the road surface is wet or slippery or covered by ice and snow.
The low range reduction gear system is operative in 4 Lo range only. This range is for extra pulling power in off road situations. Low range reduction ratio is 2.72:1.
SHIFT MECHANISM
Operating ranges are selected with a floor mounted shift lever. The shift lever is connected to the transfer case range lever by an adjustable linkage rod. A straight line shift pattern is used. Range positions are marked on the shifter bezel cover plate.
NV231 TRANSFER CASE
TRANSFER CASE IDENTIFICATION
A circular ID tag is attached to the rear case of each transfer case (Fig. 1). The ID tag provides the transfer case model number, assembly number, serial number, and low range ratio.
The transfer case serial number also represents the date of build.
RECOMMENDED LUBRICANT AND FILL LEVEL
Recommended lubricant for the NV231 transfer case is Mopart Dexron II, or ATF Plus 3, type 7176. Approximate lubricant fill capacity is 1.2 liters (2.5 pints).
The fill and drain plugs are both in the rear case (Fig. 1). Correct fill level is to the bottom edge of the fill plug hole. Be sure the vehicle is level to ensure an accurate fluid level check.
DIAGNOSIS AND TESTING
NV231 DIAGNOSIS
DIAGNOSIS CHART
Transfer case difficult to shift or will not shift into desired range.
1) Vehicle speed to great to permit shifting.
2) If vehicle was operated for an extended period in 4H mode on dry surface, driveline torque load may cause difficulty.
3) Transfer case shift linkage binding.
5) Internal transfer case components binding, worn, or damaged.
Transfer case noisy in all drive modes.
Transfer case noisy while in, or jumps out of, 4L mode.
1) Transfer case not completely engaged in 4L position.
2) Transfer case shift linkage out of adjustment.
3) Transfer case shift linkage loose or binding.
4) Range fork damaged, inserts worn, or fork is binding on the shift rail.
5) Low range gear worn or damaged.
Lubricant leaking from transfer case seals or vent.
2) Transfer case vent closed or restricted.
Abnormal tire wear. 1) Extended operation in 4H mode on dry surfaces,
CONDITION POSSIBLE CAUSE CORRECTION
1) Slow vehicle and shift into desired range.
2) Stop vehicle and shift transfer case to Neutral position. Transfer case can then be shifted to the desired mode.
3) Repair or replace linkage as necessary.
4) Insufficient or incorrect lubricant. 4) Drain and refill transfer case with the correct type and quantity of lubricant.
5) Repair or replace components as necessary.
1) Insufficient or incorrect lubricant. 1) Drain and refill transfer case with the correct type and quantity of lubricant.
1) Slow vehicle, shift transfer case to the Neutral position, and then shift into the 4L mode.
2) Adjust linkage as necessary.
3) Repair, replace, or tighten linkage components as necessary.
4) Repair or replace components as necessary.
5) Repair or replace components as necessary.
1) Transfer case overfilled. 1) Drain lubricant to the correct level.
2) Clean or replace vent as necessary.
3) Transfer case seals damaged or installed incorrectly. 3) Replace suspect seal.
1) Operate vehicle in 2H mode on dry surfaces.
REMOVAL AND INSTALLATION
TRANSFER CASE
REMOVAL
(1) Shift transfer case into Neutral. (2) Raise vehicle. (3) Drain transfer case lubricant. (4) Mark front and rear propeller shaft yokes for alignment reference.
(5) Support transmission with jack stand. (6) Remove rear crossmember and skid plate, if equipped.
(7) Disconnect front/rear propeller shafts at transfer case.
(8) Disconnect vehicle speed sensor wires. (9) Disconnect transfer case linkage rod from range lever.
(10) Disconnect transfer case vent hose (Fig. 2) and indicator switch harness, if necessary.
(11) Support transfer case with transmission jack. (12) Secure transfer case to jack with chains. (13) Remove nuts attaching transfer case to transmission.
(14) Pull transfer case and jack rearward to disengage transfer case.
(15) Remove transfer case from under vehicle.
INSTALLATION
(1) Mount transfer case on a transmission jack. (2) Secure transfer case to jack with chains. (3) Position transfer case under vehicle.
(4) Align transfer case and transmission shafts and install transfer case on transmission.
(5) Install and tighten transfer case attaching nuts to 35 N·m (Fig. 2).
(6) Connect vehicle speed sensor wires, and vent hose.
(7) Connect indicator switch harness to transfer case switch, if necessary. Secure wire harness to clips on transfer case.
(8) Align and connect propeller shafts. Tighten shaft attaching bolts to 26.5 N·m torque.
(9) Fill transfer case with correct fluid. Refer to Recommended Lubricant And Fill Level section for proper fluid and capacity.
(10) Install rear crossmember and skid plate, if equipped. Tighten crossmember bolts.
(11) Remove transmission jack and support stand. (12) Connect shift rod to transfer case range lever. (13) Adjust transfer case shift linkage. (14) Lower vehicle and verify transfer case shift operation.
SHIFT LEVER
REMOVAL
(1) Shift transfer case into 4L. (2) Remove transfer case shifter knob cap. (3) Remove nut holding shifter knob to shift lever. (4) Remove shifter knob. (5) Raise and support vehicle. (6) Loosen adjusting trunnion lock bolt and slide shift rod out of trunnion (Fig. 3). If rod lacks enough travel to come out of trunnion, push trunnion out of shift lever.
(7) Remove bolts holding shift lever to transmission.
(8) Separate shift lever from vehicle.
INSTALLATION
(1) Position shift lever on transmission. Use care when passing the shift lever through the shifter boot to prevent damage to the shifter boot.
(2) Install bolts to hold shift lever to transmission. (3) Install trunnion to shift lever, if necessary. (4) Install shift rod to trunnion, if necessary. (5) Move shift lever and transfer case to 4L position.
(6) Tighten trunnion lock bolt. (7) Lower vehicle. (8) Install shift knob on shift lever. (9) Install nut to hold shifter knob to shift lever. (10) Install shifter knob cap. (11) Verify transfer case operation.
SPEEDOMETER
REMOVAL
(1) Raise vehicle. (2) Disconnect wires from vehicle speed sensor. (3) Remove adapter clamp and screw (Fig. 4). (4) Remove speed sensor and speedometer adapter as an assembly.
(5) Remove speed sensor retaining screw and remove sensor from adapter.
(6) Remove speedometer pinion from adapter. Replace pinion if chipped, cracked, or worn.
(7) Inspect sensor and adapter O-rings (Fig. 4). Remove and discard O-rings if worn or damaged.
(8) Inspect terminal pins in speed sensor. Clean pins with Mopart electrical spray cleaner if dirty or oxidized. Replace sensor if faulty, or if pins are loose, severely corroded, or damaged.
INSTALLATION AND INDEXING
(1) Thoroughly clean adapter flange and adapter mounting surface in housing. Surfaces must be clean for proper adapter alignment and speedometer operation.
(2) Install new O-rings on speed sensor and speedometer adapter (Fig. 4), if necessary.
(3) Lubricate sensor and adapter O-rings with transmission fluid.
(4) Install vehicle speed sensor in speedometer adapter. Tighten sensor attaching screw to 2-3 N·m (15-27 in. lbs.) torque.
(5) Install speedometer pinion in adapter. (6) Count number of teeth on speedometer pinion. Do this before installing assembly in housing. Then lubricate pinion teeth with transmission fluid.
(7) Note index numbers on adapter body (Fig. 5). These numbers will correspond to number of teeth on pinion.
(8) Install speedometer assembly in housing. (9) Rotate adapter until required range numbers are at 6 o-clock position. Be sure range index numbers correspond to number of teeth on pinion gear.
(10) Install speedometer adapter clamp and retaining screw. Tighten clamp screw to 10-12 N·m (90-110 in. lbs.) torque. (11) Connect wires to vehicle speed sensor. (12) Lower vehicle and top off transmission fluid level if necessary.
FRONT OUTPUT SHAFT SEAL
REMOVAL
(1) Raise vehicle. (2) Remove front propeller shaft. Refer to Group 3, Differential and Driveline, for proper procedure.
(3) Remove front output shaft yoke. (4) Remove seal from front case with pry tool (Fig. 6).
INSTALLATION
(1) Install new front output seal in front case with Installer Tool 8143 as follows:
(a) Place new seal on tool. Garter spring on seal goes toward interior of case.
(b) Start seal in bore with light taps from hammer (Fig. 7). Once seal is started, continue tapping seal into bore until installer tool seats against case.
Adapter
REAR RETAINER BUSHING AND SEAL
REMOVAL
(1) Raise vehicle. (2) Remove rear propeller shaft. Refer to Group 3, Differential and Driveline, for proper procedure.
(3) Using a suitable pry tool or slide-hammer mounted screw, remove the rear retainer seal.
(4) Using Remover 6957, remove bushing from rear retainer (Fig. 8).
INSTALLATION
(1) Clean fluid residue from sealing surface and inspect for defects. (2) Position replacement bushing in rear retainer with fluid port in bushing aligned with slot in retainer.
(3) Using Installer 8160, drive bushing into retainer until installer seats against case (Fig. 9).
(4) Using Installer C-3995-A, install seal in rear retainer (Fig. 10).
(5) Install propeller shaft. (6) Verify proper fluid level. (7) Lower vehicle.
SPECIFICATIONS
TORQUE
DESCRIPTION TORQUE Plug, Drain/Fill . . . . . . . . . . . . . . . . . . . . . . 40 N·m Nuts, Mounting . . . . . . . . . . . . . . . . . . . . . . 35 N·m Switch, Indicator . . . . . . . . . . . . . . . . . . . . . 26 N·m