1998 DODGE RAM 1500 oil

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 front output shaft drive sprocket
retaining ring (Fig. 15).
(3) Remove the rear output shaft drive sprocket
retaining ring (Fig. 16).(4) Pull front sprocket (Fig. 17), rear sprocket, and
chain upward until clear of the front and rear output
shaft sprocket splines.
(5) Remove chain and sprockets as an assembly.
Fig. 14 Remove Oil Pick-Up Tube and Screen
1 - FRONT CASE HALF
2 - OIL SCREEN
3 - PICK-UP TUBE
Fig. 15 Remove Front Output Shaft Sprocket
Retaining Ring
1 - FRONT OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 16 Remove Rear Output Shaft Sprocket
Retaining Ring
1 - REAR OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 17 Remove Drive Chain and Sprockets
1 - FRONT CASE HALF
2 - CHAIN
3 - DRIVE SPROCKETS
21 - 548 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

(8) Remove bottom tabbed thrust washer from low
range planetary (Fig. 38).
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
3MŸ all purpose cleaner. Use compressed air to
remove solvent residue from oil feed passages in the
case halves, retainers, gears, and shafts.
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.
Examine the carrier body and pinion gears for
wear or damage. Check the pinion gear thrust wash-
ers on the pinon pins for damage. The carrier will
have to be replaced as an assembly if the body, pin-
ion 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.
Fig. 39 Input Gear And Carrier Components
1 - PLANETARY CARRIER 4 - CARRIER LOCK RING
2 - REAR THRUST WASHER 5 - CARRIER LOCK RETAINING RING
3 - FRONT THRUST WASHER 6 - INPUT GEAR
Fig. 38 Remove Bottom Input Gear Thrust Plate
1 - PLANETARY
2 - THRUST PLATE
21 - 554 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

SHIFT FORKS/HUBS/SLEEVES
Check condition of the shift forks and mode fork
shift rail (Fig. 40). Minor nicks on the shift rail can
be smoothed with 320-400 grit emery cloth.
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.
Fig. 40 Shift Forks
1 - RANGE FORK
2 - MODE FORK AND RAIL
3 - MODE SPRING
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 - NV273 21 - 555
TRANSFER CASE - NV273 (Continued)

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.
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. 43).
(3) Install the input shaft bearing into the front
case half with Installer 8151 inverted on Handle
C-4171 (Fig. 44).
(4) Install the input shaft bearing snap-ring into
the front case half with suitable snap-ring pliers.(5) Remove the front output shaft front bearing
snap-ring from the front case half.
(6) Using Installer 6953 and Handle C-4171 (Fig.
45), remove the front output shaft front bearing.
Fig. 45 Remove Front Output Shaft Front Bearing
1 - FRONT CASE HALF
2 - HANDLE C-4171
3 - INSTALLER 6953Fig. 43 Remove Input Gear Bearing
1 - FRONT CASE HALF
2 - HANDLE C-4171
3 - INSTALLER 6953
Fig. 44 Install Input Gear Bearing
1 - FRONT CASE HALF
2 - HANDLE C-4171
3 - INSTALLER 8151 (INVERTED)
21 - 556 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

(12) Install new bearing with Tool Handle C-4171
and Installer 8128 (Fig. 49). The bearing bore is
chamfered at the top. Install the bearing so it is
flush with the lower edge of this chamfer (Fig. 50).(13) Remove seal from oil pump with suitable pry
tool.
(14) Install new seal in oil pump with Installer
7888 (Fig. 51).
(15) Remove the rear output shaft bearing snap-
ring (Fig. 52) from the rear case half.
Fig. 52 Remove Rear Output Bearing Outer
Snap-Ring
1 - REAR CASE HALF
2 - REAR OUTPUT SHAFT BEARING
3 - SNAP-RING
Fig. 49 Install Front Output Shaft Rear Bearing
1 - REAR CASE HALF
2 - HANDLE C-4171
3 - INSTALLER 8128
Fig. 50 Output Shaft Rear Bearing Installation Depth
1 - BEARING (SEATED) AT LOWER EDGE OF CHAMFER
2 - CHAMFER
Fig. 51 Oil Pump Seal Installation
1 - HOUSING SEAL
2 - SPECIAL TOOL 7888
3 - OIL PUMP FEED HOUSING
21 - 558 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

(7) Install snap-ring to hold input/low range gear
into front bearing (Fig. 61).
(8) Install a new input gear seal using Installer
8841 and Handle C-4171.
(9) Install a new input gear oil seal with Installer
9036 and Handle C-4171.
SHIFT FORKS AND MAINSHAFT
(1) Lubricate mainshaft splines with recommended
transmission fluid.
(2) Coat the interior of the drive sprocket hub with
ATF+4 and install the drive sprocket drive hub (Fig.
62) onto the mainshaft.(3) Install the mode hub (Fig. 63) onto the main-
shaft.
(4) Install the mode hub retaining ring (Fig. 64)
onto the mainshaft.
Fig. 61 Install Input Gear Retaining Ring
1 - INPUT GEAR
2 - RETAINING RING
Fig. 62 Install the Drive Sprocket Drive Hub
1 - MAINSHAFT
2 - DRIVE SPROCKET DRIVE HUB
Fig. 63 Install Mode Hub
1 - MAINSHAFT
2 - MODE HUB
Fig. 64 Install Mode Hub Retaining Ring
1 - MAINSHAFT
2 - MODE HUB
3 - RETAINING RING
DRTRANSFER CASE - NV273 21 - 561
TRANSFER CASE - NV273 (Continued)

(8) Install front sprocket retaining ring (Fig. 77).
(9) Install rear sprocket retaining ring (Fig. 78).(10) Insert magnet in front case pocket (Fig. 79).
REAR CASE
(1) Install the oil pick-up tube and screen into the
rear case half.
(2) 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.
(3) Align mainshaft with the rear output shaft
bearing and align shift rail with bore in rear case.
Then install rear case (Fig. 80). Verify that the case
alignment dowels correctly seat into their mating
recesses.
Fig. 77 Install Front Output Shaft Sprocket
Retaining Ring
1 - FRONT OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 78 Install Rear Output Shaft Sprocket Retaining
Ring
1 - REAR OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 79 Case Magnet Installation
1 - MAGNET
2 - CASE POCKET
Fig. 80 Install Rear Case Half
1 - FRONT CASE HALF
2 - REAR CASE HALF
DRTRANSFER CASE - NV273 21 - 565
TRANSFER CASE - NV273 (Continued)

(4) Install 4-5 rear case-to front case bolts (Fig. 81)
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.
(5) Tighten bolts to 27-34 N´m (20-25 ft. lbs.),
(6) Install rear output bearing inner snap-ring
(Fig. 82) to output shaft.OIL PUMP AND REAR EXTENSION
(1) Install the oil pump (Fig. 83) onto the output
shaft.
(2) Engage the oil pump pick-up tube (Fig. 84) into
the oil pump. Verify that the pick-up tube o-ring is
on the tube and is correctly installed to the oil pump.
Fig. 81 Install Case Half Bolts
1 - FRONT CASE HALF
2 - REAR CASE HALF
3 - BOLTS
Fig. 82 Install Rear Bearing Inner Snap-Ring
1 - OUTPUT SHAFT
2 - REAR CASE HALF
3 - SNAP-RING
Fig. 83 Install Oil Pump
1 - REAR CASE HALF
2 - REAR OUTPUT SHAFT
3 - OIL PUMP
Fig. 84 Engage The Oil Pick-up To Oil Pump
1 - OIL PUMP
2 - OIL PICK-UP TUBE
21 - 566 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)