2003 DODGE RAM Front hub assembly

(5) Remove the mode hub retaining ring (Fig. 30)
from the output shaft.
(6) Remove the mode hub (Fig. 31) from the output
shaft.INPUT AND PLANETARY GEAR
(1) Remove input gear seal with suitable screw
and slide hammer.
(2) Remove input gear retaining ring (Fig. 32) with
heavy duty snap-ring pliers.
(3) Place front case in horizontal position. Then
remove input gear and low range gear as an assem-
bly (Fig. 33). Tap gear out of bearing with plastic
mallet, if necessary.
Fig. 30 Remove Retaining Ring
1 - OUTPUT SHAFT
2 - RETAINING RING
3 - MODE HUB
Fig. 31 Remove Mode Hub
1 - OUTPUT SHAFT
2 - MODE HUB
Fig. 32 Remove Input Gear Retaining Ring
1 - INPUT GEAR
2 - RETAINING RING
Fig. 33 Remove Input Planetary Assembly
1 - FRONT CASE
2 - INPUT PLANETARY ASSEMBLY
DRTRANSFER CASE - NV243 21 - 667
TRANSFER CASE - NV243 (Continued)

Examine the carrier body and pinion gears for
wear or damage. The carrier will have to be replaced
as an assembly if the body, pinion 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.
SHIFT FORKS/HUBS/SLEEVES
Check condition of the shift forks and mode fork
shift rail (Fig. 40). Minor nicks on the shift rail canbe smoothed with 320-400 grit emery cloth.
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 Rear Tabbed Thrust Washer Removal
1 - LOW RANGE GEAR
2 - REAR TABBED THRUST WASHER
Fig. 40 Shift Forks
1 - RANGE FORK
2 - MODE FORK AND RAIL
3 - MODE SPRING
DRTRANSFER CASE - NV243 21 - 669
TRANSFER CASE - NV243 (Continued)

(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).
(16) Install mainshaft into the transfer case (Fig.
64). Guide mainshaft through the mode and range
sleeves and into the input gear.
(17) Install new o-ring on detent plug (Fig. 65).
(18) Install detent plunger, spring, and plug (Fig.
66). Tighten the plug to 16-25 N´m (12-18 ft. lbs.).
Fig. 62 Install Range Fork And Hub Assembly
1 - RANGE HUB
2 - RANGE FORK
Fig. 63 Mode Fork And Sleeve Installation
1 - MODE SLEEVE
2 - MODE FORK AND RAIL
Fig. 64 Install Mainshaft
1 - FRONT CASE
2 - MAINSHAFT
Fig. 65 O-Ring Installation On Detent Plug
1 - O-RING
2 - DETENT PLUG
Fig. 66 Install Detent Plug, Spring, and Plunger
1 - FRONT CASE
2 - DETENT PLUG
3 - DETENT SPRING
4 - DETENT PLUNGER
21 - 676 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)

(9) Install spring and cup on shift rail (Fig. 71).
(10) Insert magnet in front case pocket (Fig. 72).
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.
(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..
Fig. 71 Shift Rail Spring And Cup Installation
1 - CUP
2 - SPRING
Fig. 72 Case Magnet Installation
1 - MAGNET
2 - CASE POCKET
Fig. 73 Install Rear Case
1 - REAR CASE
2 - FRONT CASE
21 - 678 TRANSFER CASE - NV243DR
TRANSFER CASE - NV243 (Continued)

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 - NV273
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 Transfer Case - Rear View
1 - TRANSFER CASE
2 - IDENTIFICATION TAG
21 - 688 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

(4) Remove the drive sprocket drive hub (Fig. 31)
from the mainshaft.
INPUT AND PLANETARY GEAR
(1) Remove input gear seal with suitable screw
and slide hammer.
(2) Remove input gear retaining ring (Fig. 32) with
heavy duty snap-ring pliers.(3) Place front case in horizontal position. Then
remove input gear and low range gear as an assem-
bly (Fig. 33). Tap gear out of bearing with plastic
mallet, if necessary.
Fig. 30 Remove Mode Hub
1 - MAINSHAFT
2 - MODE HUB
Fig. 31 Remove the Drive Sprocket Drive Hub
1 - MAINSHAFT
2 - DRIVE SPROCKET DRIVE HUB
Fig. 32 Remove Input Gear Retaining Ring
1 - INPUT GEAR
2 - RETAINING RING
Fig. 33 Remove Input Planetary Assembly
1 - FRONT CASE
2 - INPUT PLANETARY ASSEMBLY
DRTRANSFER CASE - NV273 21 - 697
TRANSFER CASE - NV273 (Continued)

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
DRTRANSFER CASE - NV273 21 - 699
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.
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
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
21 - 700 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)