1998 DODGE RAM 1500 Transfer case

TRANSFER CASE - NV271
TABLE OF CONTENTS
page page
TRANSFER CASE - NV271
DESCRIPTION........................447
OPERATION..........................448
DIAGNOSIS AND TESTING - TRANSFER
CASE - NV271.......................448
REMOVAL............................450
DISASSEMBLY........................450
CLEANING...........................459
INSPECTION.........................459
ASSEMBLY...........................461
INSTALLATION........................473
SPECIFICATIONS
TRANSFER CASE - NV271.............473
SPECIAL TOOLS
TRANSFER CASE NV271/NV273.........474
EXTENSION HOUSING SEAL AND DUST BOOT
REMOVAL............................476INSTALLATION........................476
FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL............................476
FRONT OUTPUT SHAFT SEAL
REMOVAL............................477
INSTALLATION........................477
POSITION SENSOR
DESCRIPTION........................477
OPERATION..........................477
REMOVAL............................478
INSTALLATION........................478
SHIFT LEVER
REMOVAL............................479
INSTALLATION........................480
ADJUSTMENTS
ADJUSTMENT - SHIFT LEVER..........481
TRANSFER CASE - NV271
DESCRIPTION
The NV271 transfer case is a part-time transfer
case with a low-range gear system. It provides three
operating ranges plus a NEUTRAL position. The low
range position provides a gear reduction ratio of
2.72:1 for increased low speed torque capability.
The gear cases and extension are all of aluminum
(Fig. 1). Drive sprockets and an interconnecting drive
chain are used to transmit engine torque to the front/
rear propeller shafts. The mainshaft, input gear and
front output shaft are supported by ball and needle
bearings.
Fig. 1 Transfer Case - Front View
1 - TRANSFER CASE
2 - MANUAL LEVER
3 - POSITION SENSOR
DRTRANSFER CASE - NV271 21 - 447

IDENTIFICATION
An identification tag (Fig. 2) is attached to the rear
case of every transfer case. 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.
OPERATION
OPERATING RANGE
Transfer case operating ranges are:
²2H (2-wheel drive)
²4H (4-wheel drive)
²4LO (4-wheel drive low range
The 2H range is for use on any road surface at any
time.
The 4H 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 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
The transfer case is operated by an adjustable floor
mounted shift linkage. The transfer case shift lever
is directly attached to the shift sector. The sector
operates the range and mode forks within the trans-
fer case.
A straight line shift pattern is used with a NEU-
TRAL detent. Lever range positions are imprinted in
the shift knob.
SHIFTING
The transfer case can be shifted between the 2H
and 4H operating ranges while the vehicle is in
motion. The vehicle must have the transmission
placed in NEUTRAL, or the clutch depressed in the
case of a manual transmission, and be moving less
than 2-3 MPH when shifting into and out of the 4L
operating range.
DIAGNOSIS AND TESTING - TRANSFER CASE -
NV271
Before beginning repair on a suspected transfer
case malfunction, check all other driveline compo-
nents beforehand.
The actual cause of a problem may be related to
such items as: front hubs, axles, propeller shafts,
wheels and tires, transmission, or clutch instead. If
all other driveline components are in good condition
and operating properly, refer to the Diagnosis Chart
for further information.
Fig. 2 Transfer Case - Rear View
1 - TRANSFER CASE
2 - IDENTIFICATION TAG
21 - 448 TRANSFER CASE - NV271DR
TRANSFER CASE - NV271 (Continued)

DIAGNOSIS CHART
Condition Possible Cause Correction
Transfer Case difficult to shift or will not
shift into desired range.1) Vehicle speed too great to permit
shifting.1) Stop vehicle and shift into desired
range. Or, reduce speed to below 3-4
km/h (2-3 mph) before attempting the
shift.
2) If vehicle was operated for an
extended period in 4H on a dry paved
surface, the driveline torque load may
be causing a bind.2) Stop vehicle and shift the
transmission into neutral. Shift the
transfer case to 2H and operate vehicle
in 2H on dry paved surfaces.
3) Transfer case external shift linkage
binding.3) Lubricate, repair, or replace linkage
bushings, or tighten loose components
as necessary.
4) Insufficient or incorrect lubricant. 4) Drain and refill to edge of fill hole
with MoparTATF +4, Automatic
Transmission fluid.
5) Internal components binding, worn,
or damaged.5) Disassemble the transfer case and
replace worn or damaged components
as necessary.
Transfer Case noisy in all operating
ranges.1) Insufficient or incorrect lubricant. 1) Drain and refill to edge of fill hole
with MoparTATF +4, Automatic
Transmission fluid.
Noisy in, or jumps out of, four wheel
drive low range.1) Transfer case not completely
engaged in 4L position.1) With the transmission in NEUTRAL,
or the clutch depressed in the case of a
manual transmission and the vehicle
moving under 3-4 km/h (2-3 mph), shift
the transfer case to NEUTRAL and then
shift into the 4L position.
2) Shift linkage out of adjustment. 2) Adjust linkage.
3) Shift linkage loose or binding. 3) Tighten, lubricate, or repair linkage as
necessary.
4) Range fork damaged, inserts worn,
or fork is binding on the shift rail.4) Disassemble unit and repair as
necessary.
5) Low range gear worn or damaged. 5) Disassemble unit and repair as
necessary.
Lubricant leaking from output shaft seal
or vent.1) Transfer case overfilled. 1) Drain lubricant to the correct level.
2) Vent closed or restricted. 2) Clear or replace vent as necessary.
3) Output shaft seals damaged or
installed incorrectly.3) Replace seal as necessary. Check to
ensure that another component, the
propeller shaft slip yoke for example, is
not causing damage to seal.
Abnormal tire wear. 1) Extended operation on hard, dry
surfaces in the 4H position.1) Operate vehicle in the 2H position on
hard, dry surfaces.
DRTRANSFER CASE - NV271 21 - 449
TRANSFER CASE - NV271 (Continued)

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)

(7) Remove rear extension bolts (Fig. 5).
(8) Remove rear extension housing (Fig. 6). Tap
extension once or twice with a plastic mallet to break
sealer bead and loosen it.OIL PUMP AND REAR CASE
(1) Disengage the oil pump pick-up tube (Fig. 7)
from the oil pump.
NOTE: The oil pump pick-up tube seals to the oil
pump with an o-ring. Verify that the o-ring was
removed with the tube and is in good condition.
Replace the o-ring if necessary.
(2) Remove the oil pump (Fig. 8).
Fig. 5 Remove Extension Housing Bolts
1 - EXTENSION HOUSING
2 - BOLTS
Fig. 6 Remove Extension Housing
1 - REAR CASE HALF
2 - EXTENSION HOUSING
Fig. 7 Disengage The Oil Pick-up From Oil Pump
1 - OIL PUMP
2 - OIL PICK-UP TUBE
Fig. 8 Remove Oil Pump
1 - REAR CASE HALF
2 - REAR OUTPUT SHAFT
3 - OIL PUMP
DRTRANSFER CASE - NV271 21 - 451
TRANSFER CASE - NV271 (Continued)

(3) Remove rear case-to-front case bolts (Fig. 9).
(4) Remove the rear output shaft bearing inner
snap-ring (Fig. 10) from the output shaft using suit-
able snap-ring pliers.
(5) Remove the rear output shaft bearing inner
snap-ring (Fig. 11) from the output shaft.
(6) Loosen rear case with pry tool to break sealer
bead. Insert tool at each end of case (Fig. 12).
Fig. 9 Remove Case Half Bolts
1 - FRONT CASE HALF
2 - REAR CASE HALF
3 - BOLTS
Fig. 10 Remove Rear Bearing Inner Snap-Ring
1 - OUTPUT SHAFT
2 - REAR CASE HALF
3 - SNAP-RING
Fig. 11 Remove Rear Bearing Inner Snap-Ring
1 - OUTPUT SHAFT
2 - REAR CASE HALF
3 - SNAP-RING
Fig. 12 Separate Front and Rear Case Halves
1 - FRONT CASE HALF
2 - REAR CASE HALF
21 - 452 TRANSFER CASE - NV271DR
TRANSFER CASE - NV271 (Continued)

(7) Unseat rear case from alignment dowels.
(8) Remove the rear case from the front case (Fig.
13).
FRONT OUTPUT SHAFT AND DRIVE CHAIN
(1) Remove the oil pick-up tube (Fig. 14) and
screen from the front case half.
(2) Remove the shift rail spring (Fig. 15).(3) Remove the front output shaft drive sprocket
retaining ring (Fig. 16).
Fig. 16 Remove Front Output Shaft Sprocket
Retaining Ring
1 - FRONT OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 13 Remove Rear Case Half
1 - FRONT CASE HALF
2 - REAR CASE HALF
Fig. 14 Remove Oil Pick-Up Tube and Screen
1 - FRONT CASE HALF
2 - OIL SCREEN
3 - PICK-UP TUBE
Fig. 15 Remove Shift Rail Spring
1 - SHIFT RAIL
2 - SPRING
DRTRANSFER CASE - NV271 21 - 453
TRANSFER CASE - NV271 (Continued)

(4) Remove the rear output shaft drive sprocket
retaining ring (Fig. 17).
(5) Pull front sprocket (Fig. 18), rear sprocket, and
chain upward until clear of the front and rear output
shaft sprocket splines.
(6) Remove chain and sprockets as an assembly.SHIFT FORKS AND MAINSHAFT
(1) Shift transfer case into NEUTRAL.
(2) Remove nut that retains the shift lever to sec-
tor shaft. Then remove shift lever (Fig. 19) and
spacer from the shaft.
(3) Remove the sector support with Socket 9033.
(4) Remove the transfer case position sensor (Fig.
20).
Fig. 17 Remove Rear Output Shaft Sprocket
Retaining Ring
1 - REAR OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 18 Remove Drive Chain and Sprockets
1 - FRONT CASE HALF
2 - CHAIN
3 - DRIVE SPROCKETS
Fig. 19 Remove Manual Shift Lever
1 - SHIFT SECTOR
2 - SECTOR SUPPORT
3 - MANUAL SHIFT LEVER
Fig. 20 Remove Position Sensor
1 - FRONT CASE
2 - POSITION SENSOR
21 - 454 TRANSFER CASE - NV271DR
TRANSFER CASE - NV271 (Continued)