1998 DODGE RAM 1500 Drive shaft

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)

OIL PUMP AND REAR CASE
(1) Remove rear case-to-front case bolts (Fig. 11).
(2) Loosen rear case with pry tool to break sealer
bead. Insert tool in slot at each end of case (Fig. 12).(3) Unseat rear case from alignment dowels.
(4) Remove rear case and oil pump assembly from
front case (Fig. 13).
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.
FRONT OUTPUT SHAFT AND DRIVE CHAIN
(1) Remove shift rail cup and spring (Fig. 14).
Fig. 11 Remove Case Bolts
1 - REAR CASE
2 - FRONT CASE
3 - BOLT
Fig. 12 Loosen Case Halves
1 - REAR CASE
2 - FRONT CASE
3 - PRY SLOTS
Fig. 13 Remove Rear Case
1 - REAR CASE
2 - FRONT CASE
Fig. 14 Shift Rail Cup And Spring Removal
1 - SHIFT RAIL
2 - SPRING
3 - CUP
DRTRANSFER CASE - NV243 21 - 487
TRANSFER CASE - NV243 (Continued)

(2) Remove front sprocket retaining ring (Fig. 15).
(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.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.
(3) Remove the front output shaft snap-ring (Fig.
18).
Fig. 15 Removing Front Sprocket Retaining Ring
1 - FRONT SPROCKET
2 - RETAINING RING
3 - FRONT OUTPUT SHAFT
Fig. 16 Remove Front Sprocket and Drive Chain
1 - FRONT DRIVE SPROCKET
2 - DRIVE CHAIN
3 - MAINSHAFT
Fig. 17 Remove Detent Plug, Spring, and Plunger
1 - FRONT CASE
2 - DETENT PLUG
3 - DETENT SPRING
4 - DETENT PLUNGER
Fig. 18 Remove Front Output Shaft Snap-ring -
Typical
1 - FRONT OUTPUT SHAFT
2 - SNAP-RING
21 - 488 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)

(9) Remove shift sector (Fig. 23).
(10) Remove the shift sector o-ring (Fig. 24).MAINSHAFT
(1) Remove the drive sprocket retaining ring (Fig.
25) from the output shaft.
(2) Remove the drive sprocket thrust washer (Fig.
26) from the output shaft.
Fig. 23 Shift Sector Removal
1 - SHIFT SECTOR
Fig. 24 Remove the Shift Sector O-Ring
1 - TRANSFER CASE FRONT HOUSING
2 - SHIFT SECTOR O-RING
Fig. 25 Remove The Drive Sprocket Retaining Ring
1 - OUTPUT SHAFT
2 - RETAINING RING
3 - DRIVE SPROCKET
Fig. 26 Remove Drive Sprocket Thrust Washer
1 - OUTPUT SHAFT
2 - THRUST WASHER
3 - DRIVE SPROCKET
21 - 490 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)

(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.
(5) Remove the mode hub retaining ring (Fig. 30)
from the output shaft.
Fig. 30 Remove Retaining Ring
1 - OUTPUT SHAFT
2 - RETAINING RING
3 - MODE HUB
Fig. 27 Remove Drive Sprocket
1 - OUTPUT SHAFT
2 - DRIVE SPROCKET
Fig. 28 Remove Clutch Gear
1 - OUTPUT SHAFT
2 - CLUTCH GEAR
3 - MODE HUB
Fig. 29 Remove Sprocket Hub
1 - OUTPUT SHAFT
2 - SPROCKET HUB
DRTRANSFER CASE - NV243 21 - 491
TRANSFER CASE - NV243 (Continued)

Inspect the shift fork wear pads (Fig. 41). The
mode and range fork pads are serviceable and can be
replaced if necessary.
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.
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 LoctiteŸ 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 Helicoiltstain-
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.
Fig. 41 Shift Fork And Wear Pad Locations
1 - RANGE FORK
2 - MODE FORK
3 - WEAR PADS (SERVICEABLE)
4 - WEAR PADS (SERVICEABLE)
Fig. 42 Low Range Annulus Gear
1 - FRONT CASE
2 - LOW RANGE ANNULUS GEAR
DRTRANSFER CASE - NV243 21 - 495
TRANSFER CASE - NV243 (Continued)

(4) Install the sprocket hub (Fig. 56) onto the out-
put shaft.
(5) Install the clutch gear (Fig. 57) onto the output
shaft.
(6) Install the drive sprocket (Fig. 58) onto the out-
put shaft.
(7) Install the drive sprocket thrust washer (Fig.
59) onto the output shaft.
Fig. 59 Install Drive Sprocket Thrust Washer
1 - OUTPUT SHAFT
2 - THRUST WASHER
3 - DRIVE SPROCKET
Fig. 56 Install Sprocket Hub
1 - OUTPUT SHAFT
2 - SPROCKET HUB
Fig. 57 Install Clutch Gear
1 - OUTPUT SHAFT
2 - CLUTCH GEAR
3 - MODE HUB
Fig. 58 Install Drive Sprocket
1 - OUTPUT SHAFT
2 - DRIVE SPROCKET
21 - 500 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)