1998 DODGE RAM 1500 Fluid

TRANSFER CASE - NV243
TABLE OF CONTENTS
page page
TRANSFER CASE - NV243
DESCRIPTION........................482
OPERATION..........................483
DIAGNOSIS AND TESTING - TRANSFER
CASE - NV243.......................483
REMOVAL............................484
DISASSEMBLY........................484
CLEANING...........................493
INSPECTION.........................493
ASSEMBLY...........................496
INSTALLATION........................505
SPECIFICATIONS
TRANSFER CASE - NV243.............505
SPECIAL TOOLS
TRANSFER CASE - NV243.............506
EXTENSION HOUSING SEAL
REMOVAL............................507
INSTALLATION........................507FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL............................507
FRONT OUTPUT SHAFT SEAL
REMOVAL............................507
INSTALLATION........................508
MODE SENSOR
DESCRIPTION........................509
OPERATION..........................509
SELECTOR SWITCH
DESCRIPTION........................510
OPERATION..........................510
SHIFT MOTOR
DESCRIPTION........................511
OPERATION..........................511
REMOVAL............................511
INSTALLATION........................511
TRANSFER CASE - NV243
DESCRIPTION
The 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:
²2WD (2-wheel drive)
²4HI (4-wheel drive)
²4LO (4-wheel drive low range)
²NEUTRAL
The 2WD range is for use on any road surface at
any time.The 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.
21 - 482 TRANSFER CASE - NV243DR

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.
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.
DIAGNOSIS AND TESTING - TRANSFER CASE - NV243
DIAGNOSIS CHART
Condition Possible Cause Correction
Transfer case difficult to shift or will
not shift into desired range.1) Transfer case electronically
controlled shift system malfunction.1) Verify proper operation per the
appropriate diagnostic manual.
2) If vehicle was operated for an
extended period in 4HI mode on
dry surface, driveline torque load
may cause difficulty.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) Insufficient or incorrect lubricant. 3) Drain and refill transfer case with
the correct quantity of MoparTAT F
+4, Automatic Transmission Fluid.
4) Internal transfer case
components binding, worn, or
damaged.4) Repair or replace components as
necessary.
Transfer case noisy in all drive
modes.1) Insufficient or incorrect lubricant. 1) Drain and refill transfer case with
the correct quantity of MoparTAT F
+4, type 9602, Automatic
Transmission Fluid.
2) Internal transfer case
components binding, worn, or
damaged.2) Repair or replace components as
necessary.
Fig. 1 Fill/Drain Plug And I.D. Tag Locations
1 - I.D. TAG
2 - FILL PLUG
3 - DRAIN PLUG
DRTRANSFER CASE - NV243 21 - 483
TRANSFER CASE - NV243 (Continued)

(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.INPUT AND PLANETARY GEAR
(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. 49 Remove Rear Output Shaft Bearing
1 - REAR CASE
2 - REMOVER/INSTALLER 8684
3 - HANDLE C-4171
Fig. 50 Install Rear Output Shaft Bearing
1 - REAR CASE
2 - REMOVER/INSTALLER 6953
3 - HANDLE C-4171
Fig. 51 Input/Low Range Gear Components
1 - SNAP-RING
2 - RETAINER PLATE
3 - INPUT GEAR
4 - LOW RANGE GEAR
5 - THRUST WASHERS
21 - 498 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)

(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.SHIFT FORKS AND MAINSHAFT
(1) Lubricate mainshaft splines with recommended
transmission fluid.
(2) Install the mode hub (Fig. 54) onto the output
shaft.
(3) Install the mode hub retaining ring (Fig. 55)
onto the output shaft.
Fig. 52 Install Input Planetary Assembly
1 - FRONT CASE
2 - INPUT PLANETARY ASSEMBLY
Fig. 53 Install Input Gear Retaining Ring
1 - INPUT GEAR
2 - RETAINING RING
Fig. 54 Install Mode Hub
1 - OUTPUT SHAFT
2 - MODE HUB
Fig. 55 Install Mode Hub Retaining Ring
1 - OUTPUT SHAFT
2 - RETAINING RING
3 - MODE HUB
DRTRANSFER CASE - NV243 21 - 499
TRANSFER CASE - NV243 (Continued)

(8) Install the drive sprocket retaining ring (Fig.
60) onto the output shaft.
(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.(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.
(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).
Fig. 63 Mode Fork And Sleeve Installation
1 - MODE SLEEVE
2 - MODE FORK AND RAIL
Fig. 60 Install The Drive Sprocket Retaining Ring
1 - OUTPUT SHAFT
2 - RETAINING RING
3 - DRIVE SPROCKET
Fig. 61 Install Shift Sector
1 - SHIFT SECTOR
Fig. 62 Install Range Fork And Hub Assembly
1 - RANGE HUB
2 - RANGE FORK
DRTRANSFER CASE - NV243 21 - 501
TRANSFER CASE - NV243 (Continued)

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 MopartGasket 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.
(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).
(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 LoctiteŸ 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
hub and tighten the clamp with Crimp Tool
C-4975-A.
Fig. 73 Install Rear Case
1 - REAR CASE
2 - FRONT CASE
Fig. 74 Install Case Bolts - Typical
1 - REAR CASE
2 - FRONT CASE
3 - BOLT
Fig. 75 Install Output Shaft Retaining Ring
1 - REAR OUTPUT SHAFT
2 - OUTPUT SHAFT BEARING
3 - RETAINING RING
4 - TRANSFER CASE
21 - 504 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)

(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..
(2) Apply bead of MopartGasket 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.
(3) Align and install rear extension on retainer
(Fig. 76).
(4) Apply MopartSilicone 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.
SPECIFICATIONS
TRANSFER CASE - NV243
TORQUE SPECIFICATIONS
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Plug, Detent 16-24 12-18 -
Plug, Drain/Fill 20-34 15-25 -
Bolt, Extension Housing 16-24 12-18 -
Bolt, Case Half 20-27 15-24 -
Screw, Oil Pump 12-16 8-12 -
Nuts, Mounting 30-41 20-30 -
Bolts, Shift Motor and
Mode Sensor Assembly16-24 12-18 -
Fig. 76 Install Rear Extension Bolts
1 - EXTENSION HOUSING
2 - TRANSFER CASE
DRTRANSFER CASE - NV243 21 - 505
TRANSFER CASE - NV243 (Continued)

EXTENSION HOUSING 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.
INSTALLATION
(1) Clean fluid residue from sealing surface and
inspect for defects.
(2) Using Installer D-163, install seal in extension
housing (Fig. 77).
(3) Install propeller shaft. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/PROPELLER SHAFT/PRO-
PELLER SHAFT - INSTALLATION)
(4) Verify proper transfer case fluid level.
(5) Lower vehicle.
FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL
The fill and drain plugs are both in the rear case
(Fig. 78).
(1) Raise vehicle.
(2) Position drain pan under transfer case.
(3) Remove drain and fill plugs and drain lubri-
cant completely.
(4) Install drain plug. Tighten plug to 20-34 N´m
(15-25 ft. lbs.).
(5) Remove drain pan.
(6)
Fill transfer case to bottom edge of fill plug open-
ing with MopartATF +4, Automatic Transmission fluid.
(7) Install and tighten fill plug to 20-34 N´m
(15-25 ft. lbs.).
(8) Lower vehicle.
FRONT OUTPUT SHAFT SEAL
REMOVAL
(1) Remove the front propeller shaft (Refer to 3 -
DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - REMOVAL).
(2) Remove the front propeller shaft seal boot
retaining clamp (Fig. 79).
Fig. 79 Remove Boot Clamp
1 - SEAL BOOT
2 - BOOT CLAMP
Fig. 77 Install Rear Seal in Extension Housing
1 - SPECIAL TOOL C-4171
2 - SPECIAL TOOL D-163
Fig. 78 Fill/Drain Plug and I.D. Tag Location
1 - I.D. TAG
2 - FILL PLUG
3 - DRAIN PLUG
DRTRANSFER CASE - NV243 21 - 507