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SENSOR RESISTANCE (ohms)
2H 4H
NEUTRAL
4L
NOT USED
REMOVAL
1172-1195
677-691
406-415
208-213
60-61(1) Raise and support the vehicle. (2) Disengage the transfer case position sensor
connector from the position sensor.
(3) Remove the position sensor from the transfer
case.
INSTALLATION
(1) Inspect the o-ring seal on the transfer case
position sensor. Replace the o-ring if necessary.
(2) Install the transfer case position sensor into the transfer case. Torque the sensor to 20-34 N·m (15-25 ft.lbs.).
(3) Engage the transfer case position sensor con-
nector to the position sensor.
(4) Lower vehicle. (5) Verify proper sensor operation.
Fig.96PositionSensorLinearMovement
1 - POSITION 1 - 10mm ±0.5mm 2 - POSITION 2 - 12mm ±0.5mm 3 - POSITION 3 - 14mm ±0.5mm 4 - POSITION 4 - 16mm ±0.5mm 5 - POSITION 5 - 18mm ±0.5mm 6 - POSITION 6 - 20mm±0.5mm - FULL EXTENSION
DR
SHIFT LEVER REMOVAL
TRANSFER CASE - NV271
21 - 655
(1) Shift transfer case into 2H. (2) Raise and support the vehicle. (3) Loosen adjusting trunnion lock bolt and slide shift rod out of trunnion. If rod lacks enough travel to come out of trunnion, push trunnion out of shift lever.
(4) Lower vehicle. (5) Remove transfer case shifter knob cap. (6) Remove nut holding shifter knob to shift lever. (7) Remove shifter knob. (8) Remove the shift boot from the shifter console. (9) Remove the bolts securing the shifter mecha-
nism to the floor pan (Fig. 97).
(10) Separate shift lever mechanism from the vehi-
cle.
1 - SHIFTER BOOT 2 - SHIFTER KNOB 3 - SHIFTER CONSOLE
Fig.97TransferCaseShifter
4 - SHIFTER MECHANISM 5 - ALIGNMENT PIN 6 - TRANSFER CASE
TRANSFER CASE - NV271
21 - 656
SHIFT LEVER (Continued) INSTALLATION(1) If
the shifter mechanism does not have a adjustment locating pin installed, align the adjust- ment channel on the shifter assembly to the locating hole in the lower shift lever and install an appropri- ately sized pin to retain the position (Fig. 98).
(2) Position shift lever in vehicle. (3) Install the bolts to hold the shifter mechanism
to the floor pan.
(4) Raise vehicle. (5) Verify that the transfer case is still in the 2H position. The 2H detent position on the transfer case shift arm is the second position from full forward.
DR
(6) Install trunnion to shift lever, if necessary. (7) Install shift rod to trunnion, if necessary. (8) Tighten the shift rod lock bolt to 10 N·m (90
in.lbs.).
(9) Remove the shifter adjustment locating pin from the adjustment channel and the locating hole.
(10) Lower vehicle. (11) Install the transfer case shifter console. (12) Install the shifter boot and the shifter knob
onto the shifter lever.
(13) Install nut to hold shifter knob to shift lever. (14) Install shifter knob cap. (15) Verify transfer case operation.
1 - SHIFTER BOOT 2 - SHIFTER KNOB 3 - SHIFTER CONSOLE
Fig.98TransferCaseShifter
4 - SHIFTER MECHANISM 5 - ALIGNMENT PIN 6 - TRANSFER CASE
DR SHIFT LEVER (Continued) ADJUSTMENTS
ADJUSTMENT - SHIFT LEVER
(1) Move shift lever into 2H position. (2) Raise vehicle. (3) Loosen shift rod lock bolt at trunnion. (4) Check shift rod fit in trunnion. Be sure rod does not bind in trunnion. Lubricate the shift rod and trunnion if necessary.
(5) Verify that transfer case shift lever is in 2H detent position. The 2H detent position on the trans- fer case shift arm is the second position from full for- ward.
(6) Align the adjustment locating hole on the lower shifter lever with the adjustment channel on the shifter bracket assembly (Fig. 99).
TRANSFER CASE - NV271
21 - 657
(7) Insert an appropriately sized pin through into the adjustment channel and through the locating hole to hold the shifter in the correct position.
(8) Tighten shift rod lock bolt to 10 N·m (90 in.
lbs.) torque.
(9) Remove the locating pin from the adjustment
channel and locating hole.
(10) Check shift linkage operation. Be sure trans- fer case shifts into and operates properly in all ranges.
1 - SHIFTER BOOT 2 - SHIFTER KNOB 3 - SHIFTER CONSOLE
Fig.99TransferCaseShifter
4 - SHIFTER MECHANISM 5 - ALIGNMENT PIN 6 - TRANSFER CASE
21 - 658
TRANSFER CASE - NV243
TRANSFER CASE - NV243
TABLE OF CONTENTS
page
DR
page
TRANSFER CASE - NV243
FLUID
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 658
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 659
DIAGNOSIS AND TESTING - TRANSFERCASE - NV243
. . . . . . . . . . . . . . . . . . . . . . . 659
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 660
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 668
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 668
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 670
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 679
SPECIFICATIONSTRANSFER CASE - NV243
. . . . . . . . . . . . . 680
SPECIAL TOOLS
TRANSFER CASE - NV241/NV243 . . . . . . . . 680
EXTENSION HOUSING BUSHING AND SEAL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 682
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 682TRANSFER CASE - NV243
DESCRIPTIONThe NV243 is an electronically controlled part-time transfer case with a low range gear reduction system. The NV243 has three operating ranges plus a NEU- TRAL position. The low range system provides a gear reduction ratio for increased low speed torque capa- bility.
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) † 4HI (4-wheel drive) † 4LO (4-wheel drive low range) † NEUTRAL The 2WD range is for use on any road surface at
any time.
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 682
FRONT OUTPUT SHAFT SEAL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 683MODE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 684
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 684SELECTOR SWITCH
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 685
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 685SHIFT MOTOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 686
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 686
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 686The 4HI and 4LO 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 slip- pery or covered by ice and snow.
The low range reduction gear system is operative in 4LO 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 dash mounted shift selector switch. The shift selector switch provides a input to the Transfer Case Control Module (TCCM) to indicate the driver’s desire to change operating ranges. The TCCM uses this input, along with input from the transfer case mounted mode sensor and information from the vehicle’s bus, to determine if a shift is permitted. If the TCCM decides the shift is permitted, the TCCM controls the shift motor, mounted to the exterior of the transfer case, to perform the shift.
DR TRANSFER CASE - NV243 (Continued) IDENTIFICATION
TRANSFER CASE - NV243
21 - 659
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.
OPERATION
The input gear is splined to the transmission out- put shaft. The input gear drives the mainshaft through the planetary assembly and range sleeve. 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.
Fig.1Fill/DrainPlugAndI.D.TagLocations-
Typical
1 - I.D. TAG 2 - FILL PLUG 3 - DRAIN PLUG
DIAGNOSIS AND TESTING - TRANSFER CASE - NV243
DIAGNOSIS CHART
Condition
Possible Cause
Correction
Transfer case difficult to shift or will not shift into desired range.
Transfer case noisy in all drive modes.
1) Transfer case electronically controlled shift system malfunction. 2) If vehicle was operated for an extended period in 4HI mode on dry surface, driveline torque load may cause difficulty. 3) Insufficient or incorrect lubricant.
4) Internal transfer case components binding, worn, or damaged. 1) Insufficient or incorrect lubricant.
2) Internal transfer case components binding, worn, or damaged.
1) Verify proper operation per the appropriate diagnostic manual. 2) Drive the vehicle in a straight line and momentarily release the accelerator. The transfer case can then be shifted to the desired mode. 3) Drain and refill transfer case with the correct quantity of MoparT ATF +4, Automatic Transmission Fluid. 4) Repair or replace components as necessary.
1) Drain and refill transfer case with the correct quantity of MoparT ATF +4, type 9602, Automatic Transmission Fluid. 2) Repair or replace components as necessary.
21 - 660
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
DR
Condition
Possible Cause
Correction
Transfer case noisy while in, or jumps out of, 4LO mode.
1) Transfer case not completely engaged in 4LO position.
2) Range fork damaged, inserts worn, or fork is binding on the shift rail. 3) Low range gear worn or damaged. 1) Transfer case overfilled.
2) Transfer case vent closed or restricted. 3) Transfer case seals damaged or installed incorrectly. 1) Extended operation in 4HI mode on dry surfaces,
Lubricant leaking from transfer case seals or vent.
Abnormal tire wear.
REMOVAL
1) While rolling 2-3 MPH and the transmission in NEUTRAL, or clutch depressed on vehicles equipped with a manual transmission, shift transfer case to the 2WD or 4HI position, and then back into the 4LO position. 2) Repair or replace components as necessary.
3) Repair or replace components as necessary. 1) Drain lubricant to the correct level. 2) Clean or replace vent as necessary. 3) Replace suspect seal.
1) Operate vehicle in 2WD mode on dry surfaces.
(1) Shift transfer case into 2WD. (2) Raise vehicle. (3) Drain transfer case lubricant. (4) Mark front and rear propeller shafts for align-
(5) Support transmission with jack stand. (6) Remove
transfer
case
the
skid plate,
if
(7) Disconnect front and rear propeller shafts at
ment reference.
equipped.
transfer case.
(8) Disconnect transfer case shift motor and mode
sensor wire connectors.
(9) Disconnect transfer case vent hose. (10) Support transfer case with transmission jack. (11) Secure transfer case to jack with chains. (12) Remove nuts attaching transfer case to trans-
mission (Fig. 2).
gage transfer case.
(13) Pull transfer case and jack rearward to disen-
(14) Remove transfer case from under vehicle.
DISASSEMBLY
Position transfer case in a shallow drain pan. Remove drain plug and drain any remaining lubri- cant remaining in case.
Fig.2RemoveTransferCase-Typical
1 - TRANSMISSION 2 - TRANSFER CASE 3 - MODE SENSOR CONNECTOR
DR TRANSFER CASE - NV243 (Continued) SHIFT MOTOR ASSEMBLY AND FRONT OUTPUT SHAFT SEAL
(1) Remove the bolts (Fig. 3) which hold the shift
motor and mode sensor assembly to the transfer case.
TRANSFER CASE - NV243
21 - 661
Fig.5RemoveSealBoot-Typical
1 - SEAL BOOT 2 - SEAL SLINGER
Fig.3RemovetheShiftMotorandModeSensor
AssemblyBolts-Typical
1 - TRANSFER CASE 2 - SHIFT MOTOR AND MODE SENSOR ASSEMBLY 3 - BOLT
(2) Remove the shift motor and mode sensor
assembly from the transfer case.
(3) Remove the front propeller shaft seal boot
retaining clamp (Fig. 4).
(4) Remove the front propeller shaft seal boot (Fig.
5).
(5) Remove the front output shaft seal slinger by bending (Fig. 6) the slinger ears away from the transfer case.
(6) Using a suitable pry tool (Fig. 7), remove the slinger from the output shaft using care not to dam- age the shaft.
Fig.6BendSlingerEars-Typical
1 - SLINGER 2 - BEND UPWARD
Fig.4RemoveBootClamp-Typical
1 - SEAL BOOT 2 - BOOT CLAMP
1 - SLINGER 2 - PRY TOOL
Fig.7RemoveSlingerFromShaft-Typical
21 - 662
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
DR
(7) Using a screw and a slide hammer, remove the
front output shaft seal.
(3) Remove output bearing retaining ring with
heavy duty snap-ring pliers (Fig. 10).
REAR EXTENSION
(1) Remove rear extension bolts (Fig. 8).
Fig.8RemoveRearExtensionBolts
1 - EXTENSION HOUSING 2 - TRANSFER CASE
(2) Remove rear extension housing (Fig. 9). Tap extension once or twice with a plastic mallet to break sealer bead and loosen it.
Fig.10RemoveOutputShaftRetainingRing
1 - REAR OUTPUT SHAFT 2 - OUTPUT SHAFT BEARING 3 - RETAINING RING 4 - TRANSFER CASE
OIL PUMP AND REAR CASE
(1) Remove rear case-to-front case bolts (Fig. 11).
Fig.9RemoveRearExtension
1 - EXTENSION HOUSING 2 - TRANSFER CASE 3 - PRY SLOT
Fig.11RemoveCaseBolts
1 - REAR CASE 2 - FRONT CASE 3 - BOLT
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 663
(2) Loosen rear case with pry tool to break sealer bead. Insert tool in slot at each end of case (Fig. 12).
FRONT OUTPUT SHAFT AND DRIVE CHAIN
(1) Remove shift rail cup and spring (Fig. 14).
Fig.12LoosenCaseHalves
Fig.14ShiftRailCupAndSpringRemoval
1 - REAR CASE 2 - FRONT CASE 3 - PRY SLOTS
1 - SHIFT RAIL 2 - SPRING 3 - CUP
(3) Unseat rear case from alignment dowels. (4) Remove rear case and oil pump assembly from
front case (Fig. 13).
(2) Remove front sprocket retaining ring (Fig. 15).
Fig.15RemovingFrontSprocketRetainingRing 1 - FRONT SPROCKET 2 - RETAINING RING 3 - FRONT OUTPUT SHAFT
Fig.13RemoveRearCase
1 - REAR CASE 2 - FRONT CASE
CAUTION: Do not remove the bolts holding the oil pump cover to the rear case half. The oil pump cover is aligned to the rear output shaft inner bear- ing race and will become mis-aligned if the bolts are loosened. If the transfer case failure has gener- ated any debris which may have become trapped in the oil pump. the rear case and oil pump assembly MUST be replaced.
(5) Remove the oil pump pickup tube.
21 - 664
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
DR
(3) Pull mainshaft, front sprocket and chain out- ward about 25.4 mm (1-inch) simultaneously (Fig. 16).
(4) Remove chain from mainshaft drive sprocket
and remove front sprocket and chain as assembly.
(3) Remove the front output shaft snap-ring (Fig.
18).
Fig.16RemoveFrontSprocketandDriveChain
1 - FRONT OUTPUT SHAFT 2 - SNAP-RING
1 - FRONT DRIVE SPROCKET 2 - DRIVE CHAIN 3 - MAINSHAFT
(4) Remove front output shaft from bearing in case
(Fig. 19).
Fig.18RemoveFrontOutputShaftSnap-ring-
Typical
SHIFT FORKS AND MAINSHAFT
(1) Loosen detent plug. (2) Remove detent plug, spring, and plunger (Fig. 17). Note that the plug has an O-ring seal. Remove and discard this seal.
Fig.19RemoveFrontOutputShaft
1 - FRONT CASE 2 - FRONT OUTPUT SHAFT
Fig.17RemoveDetentPlug,Spring,andPlunger 1 - FRONT CASE 2 - DETENT PLUG 3 - DETENT SPRING 4 - DETENT PLUNGER
DR TRANSFER CASE - NV243 (Continued)
(5) Pull mainshaft assembly out of
mode sleeve, and case (Fig. 20).
input gear,
TRANSFER CASE - NV243
21 - 665
Fig.22RangeForkAndHubRemoval
1 - RANGE HUB 2 - RANGE FORK
Fig.20RemoveMainshaft
1 - FRONT CASE 2 - MAINSHAFT
(6) Remove mode fork, mode sleeve, and shift rail as assembly (Fig. 21). Note which way the sleeve fits in the fork (long side of sleeve goes to front).
Fig.21ModeForkAndSleeveRemoval
1 - MODE SLEEVE 2 - MODE FORK AND RAIL
(7) Remove range fork retaining ring. (8) Remove range fork and hub as an assembly (Fig. 22). Note fork position for installation reference.
(9) Remove shift sector (Fig. 23). (10) Remove the shift sector o-ring (Fig. 24).
Fig.23ShiftSectorRemoval
1 - SHIFT SECTOR
Fig.24RemovetheShiftSectorO-Ring
1 - TRANSFER CASE FRONT HOUSING 2 - SHIFT SECTOR O-RING
TRANSFER CASE - NV243
21 - 666
TRANSFER CASE - NV243 (Continued) MAINSHAFTDR
(1) Remove the drive sprocket retaining ring (Fig.
25) from the output shaft.
26) from the output shaft.
(2) Remove the drive sprocket thrust washer (Fig.
Fig.25RemoveTheDriveSprocketRetainingRing 1 - OUTPUT SHAFT 2 - RETAINING RING 3 - DRIVE SPROCKET
Fig.26RemoveDriveSprocketThrustWasher
1 - OUTPUT SHAFT 2 - THRUST WASHER 3 - DRIVE SPROCKET
(3) Remove drive sprocket (Fig. 27) from the out-
put shaft.
(4) Remove the clutch gear (Fig. 28) and hub (Fig.
29) from the output shaft.
Fig.27RemoveDriveSprocket
1 - OUTPUT SHAFT 2 - DRIVE SPROCKET
Fig.28RemoveClutchGear
1 - OUTPUT SHAFT 2 - CLUTCH GEAR 3 - MODE HUB
Fig.29RemoveSprocketHub
1 - OUTPUT SHAFT 2 - SPROCKET HUB
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 667
(5) Remove the mode hub retaining ring (Fig. 30)
INPUT AND PLANETARY GEAR
from the output shaft.
shaft.
(6) Remove the mode hub (Fig. 31) from the output
and slide hammer.
(1) Remove input gear seal with suitable screw
(2) Remove input gear retaining ring (Fig. 32) with
heavy duty snap-ring pliers.
Fig.30RemoveRetainingRing
1 - OUTPUT SHAFT 2 - RETAINING RING 3 - MODE HUB
Fig.32RemoveInputGearRetainingRing
1 - INPUT GEAR 2 - RETAINING RING
(3) Place front case in horizontal position. Then remove input gear and low range gear as an assem- bly (Fig. 33). Tap gear out of bearing with plastic mallet, if necessary.
Fig.31RemoveModeHub
1 - OUTPUT SHAFT 2 - MODE HUB
Fig.33RemoveInputPlanetaryAssembly
1 - FRONT CASE 2 - INPUT PLANETARY ASSEMBLY
TRANSFER CASE - NV243
21 - 668
TRANSFER CASE - NV243 (Continued) INPUT AND PLANETARY GEARDR
(1) Remove snap-ring that retains input gear in
low range gear (Fig. 34).
(2) Remove retainer (Fig. 35). (3) Remove front tabbed thrust washer (Fig. 36). (4) Remove input gear (Fig. 37). (5) Remove rear tabbed thrust washer from low
range gear (Fig. 38).
Fig.36FrontTabbedThrustWasherRemoval
1 - FRONT TABBED THRUST WASHER
Fig.34InputGearSnap-RingRemoval
1 - INPUT GEAR SNAP-RING
Fig.35InputGearRetainerRemoval
1 - INPUT GEAR 2 - LOW RANGE GEAR 3 - RETAINER
CLEANING
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 3M™ all purpose cleaner. Use compressed air to remove solvent residue from oil feed passages in the case halves, retainers, gears, and shafts.
Fig.37InputGearRemoval
1 - INPUT GEAR 2 - LOW RANGE GEAR
INSPECTION
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 that 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. 39). 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.
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 669
be smoothed with 320-400 grit emery cloth.
Fig.38RearTabbedThrustWasherRemoval
1 - LOW RANGE GEAR 2 - REAR TABBED THRUST WASHER
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. 40). Minor nicks on the shift rail can
Fig.40ShiftForks
1 - RANGE FORK 2 - MODE FORK AND RAIL 3 - MODE SPRING
1 - PLANETARY CARRIER 2 - REAR THRUST WASHER 3 - FRONT THRUST WASHER
Fig.39InputGearandCarrierComponents 4 - CARRIER LOCK RING 5 - CARRIER LOCK RETAINING RING 6 - INPUT GEAR
21 - 670
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
Inspect the shift fork wear pads (Fig. 41). The mode and range fork pads are serviceable and can be replaced if necessary.
DR
Fig.41ShiftForkAndWearPadLocations
1 - RANGE FORK 2 - MODE FORK 3 - WEAR PADS (SERVICEABLE) 4 - WEAR PADS (SERVICEABLE)
Check both of the sleeves for wear or damage, especially on the interior teeth. Replace the sleeves if wear or damage is evident.
REAR EXTENSION HOUSING
Inspect the extension housing seal and bushing. Replace both components if either show any sign of wear or damage.
FRONT OUTPUT SHAFT AND DRIVE CHAIN
Inspect the shaft threads, sprocket teeth, and bear- ing 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 sur- faces. Rough threads on the shaft can be chased if necessary. Replace the shaft if the threads are dam- aged, 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. 42)
FRONT AND REAR CASES
Inspect the cases for wear and damage.
Fig.42LowRangeAnnulusGear
1 - FRONT CASE 2 - LOW RANGE ANNULUS GEAR
Check case condition. If leaks were a problem, look for gouges and severe scoring of case sealing sur- faces. 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 Loctite™ 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 Helicoilt stain- less 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.
ASSEMBLY
BEARINGS AND SEALS
(1) Remove the input shaft bearing (Fig. 43) from
the front case with suitable snap-ring pliers.
(2) Transfer the retaining ring to the new bearing if necessary and install the bearing into the front case.
(3) Using Installer 6436 and Handle C-4171 (Fig.
44), remove front output shaft bearing.
(4) Start front output shaft bearing in case. Then seat bearing with Handle C-4171 and Installer 6953. front output shaft bearing retaining
(5) Install
ring.
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 671
Fig.43RemoveInputGearBearing
1 - INPUT GEAR BEARING 2 - FRONT CASE
Fig.45RemoveInputGearPilotBearing
1 - DRIFT 2 - INPUT GEAR
Fig.44RemoveFrontOutputShaftBearing
1 - FRONT CASE 2 - INSTALLER 6436
3 - HANDLE C-4171(6) 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. 45).
(7) Install new pilot bearing with Remover/In-
staller 8684.
(8) Remove the front output shaft rear bearing with the screw and jaws from Remover L-4454 and Cup 8148 (Fig. 46).
Fig.46FrontOutputShaftRearBearingRemoval 1 - REAR CASE 2 - SPECIAL TOOL L-4454-1 AND L-4454-3
3 - SPECIAL TOOL 814821 - 672
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
(9) Install new bearing with Tool Handle C-4171
and Installer 5066 (Fig. 47). The bearing bore is chamfered at the top. Install the bearing so it is flush with the lower edge of this chamfer (Fig. 48).DR
(10) Remove the rear output shaft bearing from the rear case using Remover/Installer 8684 and Han- dle C-4171 (Fig. 49).
(11) Install the rear output shaft bearing (Fig. 50) into the rear case using Remover/Installer 6953 and Handle C-4171.
Fig.47OutputShaftRearBearingInstallation
1 - HANDLE C-4171
2 - OUTPUT SHAFT INNER BEARING 3 - INSTALLER 5066Fig.49RemoveRearOutputShaftBearing
1 - REAR CASE 2 - REMOVER/INSTALLER 8684
3 - HANDLE C-4171Fig.48OutputShaftRearBearingInstallationDepth 1 - BEARING (SEATED) AT LOWER EDGE OF CHAMFER 2 - CHAMFER
Fig.50InstallRearOutputShaftBearing
1 - REAR CASE 2 - REMOVER/INSTALLER 6953
3 - HANDLE C-4171DR TRANSFER CASE - NV243 (Continued) INPUT AND PLANETARY GEAR
TRANSFER CASE - NV243
21 - 673
(1) Lubricate gears and thrust washers (Fig. 51)
with recommended transmission fluid.
(2) Install first thrust washer in low range gear (Fig. 51). 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 snap-
ring.
Fig.52InstallInputPlanetaryAssembly
1 - FRONT CASE 2 - INPUT PLANETARY ASSEMBLY
Fig.51Input/LowRangeGearComponents
1 - SNAP-RING 2 - RETAINER PLATE 3 - INPUT GEAR 4 - LOW RANGE GEAR 5 - THRUST WASHERS
Fig.53InstallInputGearRetainingRing
1 - INPUT GEAR 2 - RETAINING RING
(6) Align and install low range/input gear assem- bly in front case (Fig. 52). Be sure low range gear pinions are engaged in annulus gear and that input gear shaft is fully seated in front bearing.
(7) Install snap-ring to hold input/low range gear
into front bearing (Fig. 53).
(8) Install a new input gear seal using Installer
8841 and Handle C-4171.
TRANSFER CASE - NV243
21 - 674
TRANSFER CASE - NV243 (Continued) SHIFT FORKS AND MAINSHAFT(1) Lubricate mainshaft splines with recommended
transmission fluid.
shaft.
onto the output shaft.
(2) Install the mode hub (Fig. 54) onto the output
(3) Install the mode hub retaining ring (Fig. 55)
DR
(4) Install the sprocket hub (Fig. 56) onto the out-
(5) Install the clutch gear (Fig. 57) onto the output
(6) Install the drive sprocket (Fig. 58) onto the out-
put shaft.
shaft.
put shaft.
Fig.54InstallModeHub
1 - OUTPUT SHAFT 2 - MODE HUB
Fig.56InstallSprocketHub
1 - OUTPUT SHAFT 2 - SPROCKET HUB
Fig.55InstallModeHubRetainingRing
1 - OUTPUT SHAFT 2 - RETAINING RING 3 - MODE HUB
Fig.57InstallClutchGear
1 - OUTPUT SHAFT 2 - CLUTCH GEAR 3 - MODE HUB
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 675
Fig.58InstallDriveSprocket
1 - OUTPUT SHAFT 2 - DRIVE SPROCKET
(7) Install the drive sprocket thrust washer (Fig.
59) onto the output shaft.
60) onto the output shaft.
(8) Install the drive sprocket retaining ring (Fig.
Fig.60InstallTheDriveSprocketRetainingRing 1 - OUTPUT SHAFT 2 - RETAINING RING 3 - DRIVE SPROCKET
(9) Lubricate sector shaft with transmission fluid and install shift sector in case (Fig. 61). Position slot in sector so it will be aligned with shift fork pin when shift forks are installed.
(10) Install the shift sector o-ring.
Fig.59InstallDriveSprocketThrustWasher
1 - OUTPUT SHAFT 2 - THRUST WASHER 3 - DRIVE SPROCKET
Fig.61InstallShiftSector
1 - SHIFT SECTOR
21 - 676
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
DR
(11) Assemble and install range fork and hub (Fig. 62). Be sure hub is properly seated in low range gear and engaged to the input gear.
(12) Align and insert range fork pin in shift sector
slot.
(13) Install the range fork retaining ring.
Fig.64InstallMainshaft
1 - FRONT CASE 2 - MAINSHAFT
Fig.62InstallRangeForkAndHubAssembly
1 - RANGE HUB 2 - RANGE FORK
(14) Install mode fork and shift rail onto the mode
sleeve.
(15) Install the mode fork, sleeve, and shift rail
into the transfer case (Fig. 63).
(16) Install mainshaft into the transfer case (Fig. 64). Guide mainshaft through the mode and range sleeves and into the input gear.
Fig.65O-RingInstallationOnDetentPlug
1 - O-RING 2 - DETENT PLUG
Fig.63ModeForkAndSleeveInstallation
1 - MODE SLEEVE 2 - MODE FORK AND RAIL
(17) Install new o-ring on detent plug (Fig. 65). (18) Install detent plunger, spring, and plug (Fig.
66). Tighten the plug to 16-25 N·m (12-18 ft. lbs.).
Fig.66InstallDetentPlug,Spring,andPlunger
1 - FRONT CASE 2 - DETENT PLUG 3 - DETENT SPRING 4 - DETENT PLUNGER
DR TRANSFER CASE - NV243 (Continued) FRONT OUTPUT SHAFT AND DRIVE CHAIN
(1) Install the front output shaft (Fig. 67) into the
front output shaft bearing.
(2) Install the front output shaft retaining ring
(Fig. 68) onto the output shaft.
(3) Install the new front output shaft seal with
Installer MB991168A
TRANSFER CASE - NV243
21 - 677
(6) Raise mainshaft about 2.54 cm (one inch) and
seat front sprocket on front output shaft.
Fig.67InstallFrontOutputShaft
1 - FRONT CASE 2 - FRONT OUTPUT SHAFT
Fig.69InstallFrontSprocketandDriveChain
1 - FRONT DRIVE SPROCKET 2 - DRIVE CHAIN 3 - MAINSHAFT
(7) If mainshaft and mode sleeve were unseated during chain installation, align and reseat mainshaft in input gear and hub.
(8) Install front sprocket retaining ring (Fig. 70).
Fig.68InstallFrontOutputShaftSnap-ring-Typical 1 - FRONT OUTPUT SHAFT 2 - SNAP-RING
Fig.70FrontSprocketRetainingRingInstallation 1 - FRONT SPROCKET 2 - RETAINING RING
(4) Insert front sprocket in drive chain. (5) Install drive chain around mainshaft sprocket (Fig. 69). Then position front sprocket over front shaft.
21 - 678
TRANSFER CASE - NV243 (Continued)TRANSFER CASE - NV243
(9) Install spring and cup on shift rail (Fig. 71).
DR
(4) Align oil pump with mainshaft and align shift rail with bore in rear case. Then install rear case and oil pump assembly (Fig. 73).
Fig.71ShiftRailSpringAndCupInstallation
1 - CUP 2 - SPRING
(10) Insert magnet in front case pocket (Fig. 72).
Fig.72CaseMagnetInstallation
1 - MAGNET 2 - CASE POCKET
OIL PUMP AND REAR CASE
Lubricate the oil pump components with transmis- sion fluid before installation. Prime the oil pickup tube by pouring a little oil into the tube before instal- lation.
CAUTION: Do not remove the bolts holding the oil pump cover to the rear case half. The oil pump cover is aligned to the rear output shaft inner bear- ing race and will become mis-aligned if the bolts are loosened. If the transfer case failure has gener- ated any debris which may have become trapped in the oil pump. the rear case and oil pump assembly MUST be replaced.
(1) Install new o-ring in pickup tube inlet of oil
pump.
(2) Insert oil pickup tube into the oil pump. (3) Apply bead of Mopart Gasket Maker, or equiv- alent, to mating surface of front case. Keep sealer bead width to maximum of 3/16 inch. Do not use excessive amount of sealer as excess will be displaced into case interior.
Fig.73InstallRearCase
1 - REAR CASE 2 - FRONT CASE
(5) Install 4-5 rear case-to front case bolts (Fig. 74) to hold rear case in position. Tighten bolts snug but not to specified torque at this time.
CAUTION: Verify that shift rail, and case alignment dowels are seated before installing any bolts. Case could be cracked if shaft rail or dowels are mis- aligned.
(6) Apply Loctite™ 242 to remainder of rear case- to-front case bolt threads and install bolts. Tighten bolts to 20-27 N·m (15-24 ft. lbs.),
(7) Install rear output bearing snap-ring (Fig. 75)
to output shaft.
SEAL BOOT AND SHIFT MOTOR ASSEMBLY
(1) Install the front output shaft seal slinger with Installer 8840. Install the slinger onto the shaft until the tool contacts the rear of the output shaft.
(2) Install a new seal boot clamp onto the seal
boot.
(3) Install the seal boot and clamp onto the slinger clamp with Crimp Tool
hub and tighten the C-4975-A.
(4) Position the shift motor and mode sensor
assembly onto the transfer case.
(5) Install the bolts to hold the shift motor and mode sensor assembly to the transfer case. Tighten the bolts to 16-25 N·m (12-18 ft. lbs.).
REAR EXTENSION
(1) Install new seal in rear extension housing seal
with Installer D-163 and Handle C-4171..
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 679
(3) Align and install rear extension on retainer
(Fig. 76).
Fig.74InstallCaseBolts-Typical
1 - REAR CASE 2 - FRONT CASE 3 - BOLT
Fig.76InstallRearExtensionBolts
1 - EXTENSION HOUSING 2 - TRANSFER CASE
(4) Apply Mopart Silicone Sealer to threads of rear extension housing bolts. Then install and tighten bolts to 16-24 N·m (12-18 ft. lbs.) torque.
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 onto the transmission.
(5) Install and tighten transfer case attaching nuts
to 27-34 N·m (20-25 ft. lbs.) torque.
(6) Connect the vent hose. (7) Connect the shift motor and mode sensor wir- ing connectors. Secure wire harness to clips on trans- fer case.
(8) Align and connect the propeller shafts. (9) Fill transfer case with correct fluid. (Refer to 21 - TRANSMISSION/TRANSFER CASE/FLUID - STANDARD PROCEDURE)
(10) Install skid plate, if equipped. (11) Remove transmission jack and support stand. (12) Lower vehicle and verify transfer case shift
operation.
Fig.75InstallOutputShaftRetainingRing
1 - REAR OUTPUT SHAFT 2 - OUTPUT SHAFT BEARING 3 - RETAINING RING 4 - TRANSFER CASE
(2) Apply bead of Mopart Gasket Maker, or equiv- alent, to mating surface of rear extension housing. Keep sealer bead width to maximum of 3/16 inch. Do not use excessive amount of sealer as excess could be displaced into output bearing.
TRANSFER CASE - NV243
21 - 680
TRANSFER CASE - NV243 (Continued) SPECIFICATIONSTRANSFER CASE - NV243
TORQUE SPECIFICATIONS
DR
DESCRIPTION
Plug, Detent Plug, Drain/Fill
Bolt, Extension Housing
Bolt, Case Half Screw, Oil Pump Nuts, Mounting
Bolts, Shift Motor and Mode Sensor Assembly
N-m 16-24
40-45
16-24
20-27
12-16
30-41
16-24SPECIAL TOOLS
TRANSFER CASE - NV241/NV243
Ft. Lbs. 12-18
30-40
12-18
15-24
8-12
20-30
12-18In. Lbs.
Installer,Bearing-6953
Handle,Universal-C-4171
Installer,Seal-C-4210
Installer,Seal-6888
Remover,Bushing-6957
DR TRANSFER CASE - NV243 (Continued)
TRANSFER CASE - NV243
21 - 681
Installer,Bushing-8157
Remover-L-4454
Installer,Seal-D-163
Cup-8148
Installer,Seal-7884
Installer,PumpHousingSeal-7888
Installer,Bushing-5066
Plug,Extension-C-293-3
21 - 682
TRANSFER CASE - NV243
DR
EXTENSION HOUSING BUSHING AND SEAL REMOVAL
(1) Raise and support vehicle. (2) Remove rear propeller shaft. (Refer to 3 - DIF- FERENTIAL & DRIVELINE/PROPELLER SHAFT/ PROPELLER SHAFT - REMOVAL)
(3) Using a suitable pry tool or slide-hammer
mounted screw, remove the extension housing seal.
(4) Using Remover 8158, remove bushing from
extension housing.
INSTALLATION
(1) Clean fluid residue from sealing surface and
inspect for defects.
(2) Position replacement bushing in extension housing with fluid port in bushing aligned with slot in housing.
(3) Using Installer 8157, drive bushing into hous-
ing until installer seats against case.
(4) Using Installer D-163, install seal in extension
housing (Fig. 77).
FLUID STANDARD PROCEDURE - FLUID DRAIN AND REFILL
The fill and drain plugs are both in the rear case
(Fig. 78).
Fig.78Fill/DrainPlugandI.D.TagLocation-
Typical
1 - I.D. TAG 2 - FILL PLUG 3 - DRAIN PLUG
(1) Raise vehicle. (2) Position drain pan under transfer case. (3) Remove drain and fill plugs and drain lubri-
(4) Install drain plug. Tighten plug to 41-54 N·m
cant completely.
(30-40 ft. lbs.).
(5) Remove drain pan. (6) Fill transfer case to bottom edge of fill plug opening with Mopart ATF +4, Automatic Transmis- sion fluid.
(7) Install and tighten fill plug to 41-54 N·m
(30-40 ft. lbs.).
(8) Lower vehicle.
Fig.77InstallRearSealinExtensionHousing
1 - SPECIAL TOOL C-4171
2 - SPECIAL TOOL D-163(5) Install propeller shaft. (Refer to 3 - DIFFER- ENTIAL & DRIVELINE/PROPELLER SHAFT/PRO- PELLER SHAFT - INSTALLATION)
(6) Verify proper transfer case fluid level. (7) Lower vehicle.
DR
TRANSFER CASE - NV243
21 - 683
FRONT OUTPUT SHAFT SEAL REMOVAL
(1) Remove the front propeller shaft (Refer to 3 - DRIVELINE/PROPELLER
DIFFERENTIAL SHAFT/PROPELLER SHAFT - REMOVAL).
(2) Remove the front propeller shaft seal boot
retaining clamp (Fig. 79).
(3) Remove the front propeller shaft seal boot (Fig.
80).
(4) Remove the front output shaft seal slinger by bending (Fig. 81) the slinger ears away from the transfer case.
(5) Using a suitable pry tool (Fig. 82), remove the slinger from the output shaft using care not to dam- age the shaft.
Fig.81BendSlingerEars
1 - SLINGER 2 - BEND UPWARD
Fig.79RemoveBootClamp
1 - SEAL BOOT 2 - BOOT CLAMP
Fig.82RemoveSlingerFromShaft
1 - SLINGER 2 - PRY TOOL
(6) Using a screw and a slide hammer, remove the
front output shaft seal.
INSTALLATION
(1) Install the new front output shaft seal with
Installer MB991168A
(2) Install the front output shaft seal slinger with Installer 8840. Install the slinger onto the shaft until the tool contacts the rear of the output shaft.
(3) Install a new seal boot clamp onto the seal
boot.
(4) Install the seal boot and clamp onto the slinger clamp with Crimp Tool
hub and tighten the C-4975-A.
(5) Install front propeller shaft (Refer to 3 - DIF- FERENTIAL & DRIVELINE/PROPELLER SHAFT/ PROPELLER SHAFT - INSTALLATION).
Fig.80RemoveSealBoot
1 - SEAL BOOT 2 - SEAL SLINGER
21 - 684
TRANSFER CASE - NV243
DR
MODE SENSOR DESCRIPTION
The transfer case mode sensor (Fig. 83) is an elec- tronic device whose output can be interpreted to indi- cate the shift motor shaft’s rotary position. The sensor consists of a magnetic ring and four Hall Effect Transistors to create a 4 channel digital device (non-contacting) whose output converts the motor shaft position into a coded signal. The TCCM must supply 5VDC (+/- 0.5v) to the sensor and monitor the shift motor position. The four channels are denoted A, B, C, and D. The sensor is mechanically linked to the shaft of the cam which causes the transfer case shifting. The mode sensor draws less than 53 mA.
OPERATION
During normal vehicle operation, the Transfer Case Control Module (TCCM) monitors the mode sensor outputs at least every 250 (+/-50) milliseconds when the shift motor is stationary and 400 microseconds when the shift motor is active. A mode sensor signal between 3.8 Volts and 0.8 Volts is considered to be undefined.
Refer to SECTOR ANGLES vs. TRANSFER CASE POSITION for the relative angles of the transfer case shift sector versus the interpreted transfer case gear operating mode. Refer to MODE SENSOR CHAN- NEL STATES for the sensor codes returned to the TCCM for each transfer case mode sensor position. The various between gears positions can also be referred as the transfer case’s coarse position. These coarse positions come into play during shift attempts.
Fig.83ModeSensor
1 - MODE SENSOR
SECTOR ANGLES VS. TRANSFER CASE POSITION
Shaft Angle (Degrees)
Transfer Case Position
+40
+20
-204LO
2WD/AWD
4HI
Transfer Case Angle (degrees) Between Gears
+40 (4LO)
Between Gears Between Gears +20 (NEUTRAL) Between Gears Between Gears 0 (2WD/AWD) Between Gears Between Gears
-20 (4HI)
Between Gears Between Gears
MODE SENSOR CHANNEL STATES
Sensor Channel A
Sensor Channel B
Sensor Channel C
Sensor Channel D
DR
TRANSFER CASE - NV243
21 - 685
SELECTOR SWITCH DESCRIPTION
The selector switch assembly (Fig. 84) is mounted in the left side of the vehicle’s Instrument Panel (IP) and consists of a rotary knob connected to a resistive network for the mode and range shift selections. Also located in this assembly is a recessed, normally open momentary switch for making shifts into and out of transfer case NEUTRAL. A pen, or similar instru- ment, is used to make a NEUTRAL shift selection, thus reducing the likelihood of an inadvertent shift request.
The selector switch also contains four light emit- ting diode’s (LED’s) to indicate the transfer case posi- tion and whether a shift is in progress.
OPERATION
As the position of the selector switch varies, the resistance between the Mode Sensor supply voltage pin and the Mode Sensor output will vary. Hardware, software, and calibrations within the Transfer Case Control Module (TCCM) are provided that interpret the selector switch resistance as given in the table below: SELECTOR SWITCH INTERPRETATION
SELECTOR SWITCH INTERPRETATION
Step
Resistance
Range (ohms)
Required
Interpretation
<200
400-700
1050-1450
1850-2300
3050-5950
9.5-12.5K>15.5K
Shorted
NEUTRAL
4LO 4HI
2WD (Default)
In between positions
Open
Fig.84TransferCaseSelectorSwitch
1 - SELECTOR SWITCH
For resistances between the ranges B-E shown for each valid position (T-Case NEUTRAL, 4LO, 4HI, 2WD), the TCCM may interpret the resistance as:
† either of the neighboring valid positions. † as an invalid fault position. For resistances between the ranges E and F shown for 2WD and in-between positions, the TCCM may interpret the resistance as:
† the 2WD position. † an invalid fault position. † a valid in-between position. For resistances between the ranges F and G shown for in-between positions and fault condition (open), the TCCM may interpret the resistance as:
† a valid in-between position. † an invalid fault position. For resistances between the ranges A and B shown for the fault condition (short) and , T-Case NEU- TRAL, the TCCM may interpret the resistance as:
† the T-Case NEUTRAL position. † an invalid fault position. The LED’s in the selector assembly are illuminat- ed/flashed in the following manner to indicate a par- ticular condition or state. † A solidly illuminated LED indicates a success- fully completed shift and the current operating mode of the transfer case. While a shift has been requested but not yet completed, the LED for the desired trans- fer case position is flashed.
21 - 686
TRANSFER CASE - NV243
SELECTOR SWITCH (Continued) † A flashing operating mode LED for the desired gear indicates that a shift to that position has been requested, but all of the driver controllable conditions have not been met. This is in an attempt to notify the driver that the transmission needs to be put into NEUTRAL, the vehicle speed is too great, or some other condition outlined (other than a diagnostic fail- ure that would prevent this shift) elsewhere (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MOD- ULES/TRANSFER CASE CONTROL MODULE - OPERATION) is not met. Note that this flashing will continue indefinitely until the conditions are eventu- ally met, or the selector switch position is changed, or longer allow the if diagnostic requested shift. † If the driver attempts to make a shift into trans- fer case NEUTRAL, and any of the driver controlla- ble conditions are not met, the request will be ignored until all of the conditions are met or until the NEUTRAL select button is released. Additionally the neutral lamp will flash, or begin to flash while the button is depressed and operator controllable conditions are not being met. All of the LED’s except the Neutral will flash if any of the operator control- lable conditions for shifting are not met while the Neutral button is depressed. This 9toggle9 type of fea- ture is necessary because the TCCM would interpret into another request transfer case NEUTRAL has completed. † No LED’s illuminated indicate a fault in theimmediately after the shift
routines no
transfer case control system.
SHIFT MOTOR DESCRIPTION
The shift motor (Fig. 85) consists of a permanent magnet D.C. motor with gear reduction to convert a high speed-low torque device into a low speed-high torque device. The output of the device is coupled to a shaft which internally moves the mode and range forks that change the transfer case operating ranges. The motor is rated at 25 amps maximum at 72° F with 10 volts at the motor leads.
OPERATION
The transfer case shift motor responds to the Transfer Case Control Module (TCCM) commands to move the transfer case shift sector bi-directionally, as required, to obtain the transfer case operating mode indicated by the instrument panel mounted selector switch.
DR
Fig.85ShiftMotor-ShownInverted-Typical
1 - SHIFT MOTOR
REMOVAL
(1) Raise the vehicle on a suitable hoist. (2) Disengage the wiring connectors from the shift
motor and mode sensor.
(3) Remove the bolts holding the shift motor and
mode sensor assembly onto the transfer case.
(4) Separate the shift motor and mode sensor
assembly from the transfer case.
INSTALLATION
(1) Verify that the shift sector o-ring is clean and properly positioned over the shift sector and against the transfer case.
(2) Position the shift motor and mode sensor
assembly onto the transfer case.
(3) Install the bolts to hold the assembly onto the transfer case. Tighten the bolts to 16-24 N·m (12-18
ft.lbs.).CAUTION: If the original shift motor and mode sen- sor assembly bolts are reused, be sure to use MoparT Lock & Seal or Loctite™ 242 to replenish the lock patch material originally found on the bolts
(4) Engage the wiring connectors to the shift motor
and mode sensor.
(5) Refill the transfer case as necessary. (6) Lower vehicle and verify transfer case opera-
tion.
DR
TRANSFER CASE - NV273
21 - 687
TRANSFER CASE - NV273
TABLE OF CONTENTS
page
page
TRANSFER CASE - NV273
FLUID
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 687
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 688
DIAGNOSIS AND TESTING - TRANSFERCASE - NV273
. . . . . . . . . . . . . . . . . . . . . . . 688
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 689
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 698
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 699
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 713
SPECIFICATIONSTRANSFER CASE - NV273
. . . . . . . . . . . . . 713
SPECIAL TOOLS
TRANSFER CASE NV271/NV273 . . . . . . . . . 714
EXTENSION HOUSING SEAL AND DUST BOOT
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 716
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 716TRANSFER CASE - NV273
DESCRIPTIONThe NV273 is an electronically controlled part-time transfer case with a low range gear reduction system. The NV273 has three operating ranges plus a NEU- TRAL position. The low range system provides a gear reduction ratio for increased low speed torque capa- bility.
The geartrain is mounted in two aluminum case halves attached with bolts. The mainshaft front and rear bearings are mounted in aluminum case halves.
OPERATING RANGES
Transfer case operating ranges are: † 2WD (2-wheel drive) † 4HI (4-wheel drive) † 4LO (4-wheel drive low range) † NEUTRAL The 2WD range is for use on any road surface at
any time.
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 716
FRONT OUTPUT SHAFT SEAL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 717
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 717MODE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 718
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 718SELECTOR SWITCH
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 719
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 719SHIFT MOTOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 720
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 720
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 720The 4HI and 4LO 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 slip- pery or covered by ice and snow.
The low range reduction gear system is operative in 4LO 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 dash mounted shift selector switch. The shift selector switch provides a input to the Transfer Case Control Module (TCCM) to indicate the driver’s desire to change operating ranges. The TCCM uses this input, along with input from the transfer case mounted mode sensor and information from the vehicle’s bus, to determine if a shift is permitted. If the TCCM decides the shift is permitted, the TCCM controls the shift motor, mounted to the exterior of the transfer case, to perform the shift.
TRANSFER CASE - NV273
21 - 688
TRANSFER CASE - NV273 (Continued) IDENTIFICATIONDR
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.
OPERATION
The input gear is splined to the transmission out- put shaft. The input gear drives the mainshaft through the planetary assembly and range sleeve. 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.
Fig.1TransferCase-RearView
1 - TRANSFER CASE 2 - IDENTIFICATION TAG
DIAGNOSIS AND TESTING - TRANSFER CASE - NV273
DIAGNOSIS CHART
Condition
Possible Cause
Correction
Transfer case difficult to shift or will not shift into desired range.
Transfer case noisy in all drive modes.
1) Transfer case electronically controlled shift system malfunction. 2) If vehicle was operated for an extended period in 4HI mode on dry surface, driveline torque load may cause difficulty. 3) Insufficient or incorrect lubricant.
4) Internal transfer case components binding, worn, or damaged. 1) Insufficient or incorrect lubricant.
2) Internal transfer case components binding, worn, or damaged.
1) Verify proper operation per the appropriate diagnostic manual. 2) Drive the vehicle in a straight line and momentarily release the accelerator. The transfer case can then be shifted to the desired mode. 3) Drain and refill transfer case with the correct quantity of MoparT ATF
