1998 DODGE RAM 1500 ECU

REMOVAL
(1) Raise and support vehicle.
(2) Remove skid plate, if equipped. (Refer to 13 -
FRAMES & BUMPERS/FRAME/TRANSFER CASE
SKID PLATE - REMOVAL)
(3) Position drain oil container under transfer
case.
(4) Remove transfer case drain plug and drain
lubricant into container.
(5) Disconnect vent hose and transfer case position
sensor connector.
(6) Disconnect shift rod from grommet in transfer
case shift lever, or from floor shift arm whichever
provides easy access. Use channel lock style pliers to
press rod out of lever grommet.
(7) Support transmission with jack stand.
(8) Mark front and rear propeller shafts for assem-
bly reference.
(9) Remove front and rear propeller shafts. (Refer
to 3 - DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - REMOVAL)
(10) Support transfer case with suitable jack.
Secure transfer case to jack with safety chains.
(11) Remove nuts attaching transfer case to trans-
mission.
(12) Move transfer case assembly rearward until
free of transmission output shaft.
(13) Lower jack and move 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.
COMPANION FLANGE AND EXTENSION HOUSING
(1) Install two bolts 180É apart into the front out-
put shaft companion flange.
(2) Place holder over the bolts and against the
companion flange (Fig. 3).
(3) Remove and discard the front companion flange
nut.
(4) Remove the companion flange from the front
output shaft. It may be necessary to use Flange
puller 8992 to remove the companion flange.
(5) Use a suitable chisel or pry tool to remove the
rear extension housing dust boot (Fig. 4).
(6) Use a suitable chisel or pry tool to remove the
rear extension housing seal.
Fig. 3 Remove Companion Flange Nut
1 - HOLDER 6719
2 - BOLTS
Fig. 4 Remove Extension Housing Dust Boot
1 - EXTENSION HOUSING
2 - DUST BOOT
21 - 450 TRANSFER CASE - NV271DR
TRANSFER CASE - NV271 (Continued)

DRIVE CHAIN
Examine the drive chain and shaft bearings.
replace the chain if 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. 43)
FRONT CASE AND REAR CASE
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 HelicoilŸ 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 snap-ring from
the front case half with suitable snap-ring pliers.
(2)
Remove the input shaft bearing from the front case
half with Installer 6953 and Handle C-4171 (Fig. 44).
(3) Install the input shaft bearing into the front
case half with Installer 8151 inverted on Handle
C-4171 (Fig. 45).
(4) Install the input shaft bearing snap-ring into
the front case half with suitable snap-ring pliers.
Fig. 43 Low Range Annulus Gear
1 - FRONT CASE
2 - LOW RANGE ANNULUS GEARFig. 44 Remove Input Gear Bearing
1 - FRONT CASE HALF
2 - HANDLE C-4171
3 - INSTALLER 6953
Fig. 45 Install Input Gear Bearing
1 - FRONT CASE HALF
2 - HANDLE C-4171
3 - INSTALLER 8151 (INVERTED)
DRTRANSFER CASE - NV271 21 - 461
TRANSFER CASE - NV271 (Continued)

(12) Install mainshaft into the transfer case (Fig.
70). Guide mainshaft through the mode and range
sleeves and into the input gear.
(13) Install the transfer case position sensor (Fig.
71). Tighten the sensor to 20-34 N´m (15-25 ft. lbs.)
torque.(14) Install manual shift lever and spacer onto sec-
tor shaft (Fig. 72).
(15) Install washer and nut on sector shaft to
secure shift lever. Apply 1-2 drops MopartLock N'
Seal, or equivalent, to nut threads before installation.
Then tighten nut to 27-34 N´m (20-25 ft. lbs.) torque.
(16) Install new o-ring on detent plug (Fig. 73).
Fig. 73 O-Ring Installation On Detent Plug
1 - O-RING
2 - DETENT PLUG
Fig. 70 Install Mainshaft Assembly
1 - FRONT CASE HALF
2 - MAINSHAFT ASSEMBLY
Fig. 71 Install Position Sensor
1 - FRONT CASE
2 - POSITION SENSOR
Fig. 72 Install Manual Shift Lever
1 - SHIFT SECTOR
2 - SECTOR SUPPORT
3 - MANUAL SHIFT LEVER
21 - 468 TRANSFER CASE - NV271DR
TRANSFER CASE - NV271 (Continued)

SHIFT LEVER
REMOVAL
(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.
Fig. 97 Transfer Case Shifter
1 - SHIFTER BOOT 4 - SHIFTER MECHANISM
2 - SHIFTER KNOB 5 - ALIGNMENT PIN
3 - SHIFTER CONSOLE 6 - TRANSFER CASE
DRTRANSFER CASE - NV271 21 - 479

Condition Possible Cause Correction
Transfer case noisy while in, or
jumps out of, 4LO mode.1) Transfer case not completely
engaged in 4LO position.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) Range fork damaged, inserts
worn, or fork is binding on the shift
rail.2) Repair or replace components as
necessary.
3) Low range gear worn or
damaged.3) Repair or replace components as
necessary.
Lubricant leaking from transfer case
seals or vent.1) Transfer case overfilled. 1) Drain lubricant to the correct
level.
2) Transfer case vent closed or
restricted.2) Clean or replace vent as
necessary.
3) Transfer case seals damaged or
installed incorrectly.3) Replace suspect seal.
Abnormal tire wear. 1) Extended operation in 4HI mode
on dry surfaces,1) Operate vehicle in 2WD mode on
dry surfaces.
REMOVAL
(1) Shift transfer case into 2WD.
(2) Raise vehicle.
(3) Drain transfer case lubricant.
(4) Mark front and rear propeller shafts for align-
ment reference.
(5) Support transmission with jack stand.
(6) Remove the transfer case skid plate, if
equipped.
(7) Disconnect front and rear propeller shafts at
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).
(13) Pull transfer case and jack rearward to disen-
gage transfer case.
(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. 2 Remove Transfer Case - Typical
1 - TRANSMISSION
2 - TRANSFER CASE
3 - MODE SENSOR CONNECTOR
21 - 484 TRANSFER CASE - NV243DR
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) 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)

CONDITION POSSIBLE CAUSE CORRECTION
Lubricant leaking from transfer case
seals or vent.1) Transfer case overfilled. 1) Drain lubricant to the correct
level.
2) Transfer case vent closed or
restricted.2) Clean or replace vent as
necessary.
3) Transfer case seals damaged or
installed incorrectly.3) Replace suspect seal.
Transfer case will not shift through
4HI (Part-time) range.1) Incomplete shift due to drivetrain
torque load.1) Drive in a straight line and
momentarily release the accelerator
pedal to complete the shift.
2) Incorrect tire pressure. 2) Correct tire pressure as
necessary.
3) Excessive tire wear. 3) Correct tire condition as
necessary.
4) Excessive vehicle loading. 4) Correct as necessary.
REMOVAL
(1) Shift transfer case into AWD.
(2) Raise vehicle.
(3) Drain transfer case lubricant.
(4) Mark front and rear propeller shafts for align-
ment reference.
(5) Support transmission with jack stand.
(6)
Remove the transfer case skid plate, if equipped.
(7) Disconnect front and rear propeller shafts at
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).(13) Pull transfer case and jack rearward to disen-
gage transfer case.
(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.
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.
Fig. 2 Remove Transfer Case - Typical
1 - TRANSMISSION
2 - TRANSFER CASE
3 - MODE SENSOR CONNECTOR
Fig. 3 Remove the Shift Motor and Mode Sensor
Assembly Bolts - Typical
1 - TRANSFER CASE
2 - SHIFT MOTOR AND MODE SENSOR ASSEMBLY
3 - BOLT
21 - 514 TRANSFER CASE - NV244 GENIIDR
TRANSFER CASE - NV244 GENII (Continued)