2001 DODGE RAM torque

TRANSFER CASE - NV231HD
TABLE OF CONTENTS
page page
TRANSFER CASE - NV231HD
DESCRIPTION..........................820
OPERATION............................820
DIAGNOSIS AND TESTING................821
TRANSFER CASE.....................821
REMOVAL.............................822
DISASSEMBLY..........................822
CLEANING.............................831
INSPECTION...........................832
ASSEMBLY............................834
INSTALLATION..........................847
SPECIFICATIONS........................848
SPECIAL TOOLS........................849EXTENSION HOUSING BUSHING AND SEAL
REMOVAL.............................850
INSTALLATION..........................850
FLUID
STANDARD PROCEDURE.................851
FLUID DRAIN AND REFILL...............851
FRONT OUTPUT SHAFT SEAL
REMOVAL.............................851
INSTALLATION..........................852
SHIFT LEVER
REMOVAL.............................852
INSTALLATION..........................853
ADJUSTMENTS.........................853
TRANSFER CASE - NV231HD
DESCRIPTION
The NV231HD 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 synchronizer mechanism consists of a brass
stop ring, synchro hub, and the sliding clutch. The
synchronizer components allow the transfer case to
be shifted between the 2H and 4H operating ranges
while the vehicle is in motion.
The gear cases, retainer and extension are all of
aluminum. 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 nee-
dle bearings.
IDENTIFICATION
An identification tag (Fig. 1) 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 RANGES
Transfer case operating ranges are:
²4x2 (2-wheel drive)
²4x4 (4-wheel drive)
²4 Lo (4-wheel drive low range
Fig. 1 Transfer Case Identification Tag - Typical
1 - I.D. TAG
2 - FILL PLUG
3 - DRAIN PLUG
21 - 820 TRANSFER CASE - NV231HDBR/BE

The 4x2 range is for use on any road surface at
any time.
The 4x4 and 4 Lo 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 4 Lo range only. This range is for extra pulling
power in off road situations. Low range reduction
ratio is 2.72:1.
A front axle disconnect system is used to achieve
two-wheel drive mode. The axle disconnect vacuum
motor is actuated by a vacuum switch on the transfer
case. The switch is operated by the transfer case
range rod.
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 synchronizer components allow the transfer
case to 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 trans-
mission, and be moving less than 2-3 MPH when
shifting into the 4L operating range.
DIAGNOSIS AND TESTING - TRANSFER CASE
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.
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, type 9602,
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, type 9602,
Automatic Transmission fluid.
BR/BETRANSFER CASE - NV231HD 21 - 821
TRANSFER CASE - NV231HD (Continued)

(8) Clean gasket sealer residue from retainer and
inspect retainer for cracks or other damage.
(9) Applya3mm(1/8 in.) bead of MopartGasket
Maker, or equivalent silicone adhesive, to sealing
surface of retainer.
(10) Align cavity in seal retainer with fluid return
hole in front of case.
CAUTION: Do not block fluid return cavity on seal-
ing surface of retainer when applying MoparTGas-
ket Maker, or equivalent silicone adhesive sealer.
Seal failure and fluid leak can result.
(11) Install bolts to hold retainer to transfer case
(Fig. 59). Tighten to 21 N´m (16 ft. lbs.) of torque.
SHIFT FORKS AND MAINSHAFT
(1) Lubricate mainshaft splines with recommended
transmission fluid.
(2) Install drive sprocket on mainshaft (Fig. 60).
(3) Install brass stop ring on drive sprocket (Fig.
61).
(4) Install 3 synchro struts and 2 springs in hub as
follows:
(a) Insert first strut in hub (Fig. 62). Strut
shoulders rest (and slide) on sides hub slot as
shown.
(b) Insert hooked end of first spring in center of
strut to secure it. Then work spring into hub (Fig.
63).
Fig. 58 Install Input Gear Snap-Ring
1 - INPUT GEAR
2 - SNAP-RING
Fig. 59 Install Front Bearing Retainer
1 - FRONT BEARING RETAINER
Fig. 60 Drive Sprocket Installation
1 - MAINSHAFT
2 - DRIVE SPROCKET
Fig. 61 Synchro Stop Ring Installation
1 - BRASS STOP RING
2 - DRIVE SPROCKET
21 - 838 TRANSFER CASE - NV231HDBR/BE
TRANSFER CASE - NV231HD (Continued)

(15) Install vacuum/indicator switch (Fig. 73).
Tighten switch to 20-34 N´m (15-25 ft. lbs.) torque.
Install new O-ring on switch beforehand, if necessary.
(16) Install new sector shaft O-ring and O-ring
retainer in sector shaft bore (Fig. 74). Lubricate
O-ring with transmission fluid or petroleum jelly
after installation.
(17) Install shift lever on sector shaft (Fig. 75).
(18) 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.(19) Install poppet plunger and spring (Fig. 76).
(20) Install new O-ring on poppet screw and install
screw in front case (Fig. 77). Tighten screw to 16-24
N´m (12-18 ft. lbs.).
Fig. 73 Vacuum/Indicator Switch Installation
1 - 1-1/16º SOCKET
2 - INDICATOR SWITCH
Fig. 74 Sector Shaft O-Ring And Retainer Installation
1 - SECTOR SHAFT BORE
2 - O-RING
3 - O-RING RETAINER
Fig. 75 Shift Lever Installation
1 - SHIFT LEVER
2 - NUT/WASHER
Fig. 76 Poppet Plunger And Spring Installation
1 - POPPET PLUNGER AND SPRING
Fig. 77 O-Ring Installation On Poppet Plunger
Screw
1 - O-RING
2 - PLUNGER SCREW
21 - 842 TRANSFER CASE - NV231HDBR/BE
TRANSFER CASE - NV231HD (Continued)

(5) Align oil pump with mainshaft and align shift
rail with bore in rear case. Then install rear case and
oil pump assembly (Fig. 86). Be sure oil pump and
pickup tube remain in position during case installa-
tion.
(6) Install 4-5 rear case-to front case bolts to hold
rear case in position. Tighten bolts snug but not to
specified torque at this time.
CAUTION: Verify that shift rail (Fig. 87), and case
alignment dowels are seated before installing any
bolts. Case could be cracked if shaft rail or dowels
are misaligned.(7) Verify that oil pump is aligned and seated on
rear case. Reposition pump if necessary.
(8) Check stud at end of case halves (Fig. 88). If
stud was loosened or came out during disassembly,
apply LoctiteŸ 242 to stud threads and reseat stud
in case.
(9) Apply LoctiteŸ 242 to remainder of rear case-
to-front case bolt threads and install bolts. Be sure
lock washers are used on studs/bolts at case ends.
Tighten bolts, or stud nuts as follows:
²flange head bolts to 47-61 N´m (35-45 ft. lbs.)
²all other bolts/nuts to 27-34 N´m (20-25 ft. lbs.)
(10) Install oil pump retaining ring on mainshaft
(Fig. 89).
Fig. 86 Rear Case And Oil Pump Installation
1 - MAINSHAFT
2 - OIL PUMP
3 - REAR CASE
Fig. 87 Shift Rail Seated In Rear Case Bore
1 - REAR CASE
2 - SHIFT RAIL
Fig. 88 Washer Installation On Case Stud And
Dowel Bolts
1 - CASE STUD/BOLT
2 - WASHER
Fig. 89 Oil Pump Retaining Ring Installation
1 - RETAINING RING
2 - OIL PUMP
BR/BETRANSFER CASE - NV231HD 21 - 845
TRANSFER CASE - NV231HD (Continued)

(11) Install rear output bearing and snap-ring to
output shaft.
COMPANION FLANGE
(1) Install companion flange seal on front shaft
(Fig. 90).
(2) Install companion flange on front shaft (Fig.
91). Then install and tighten flange nut to 176-271
N´m (130-200 ft. lbs.) torque.
REAR RETAINER AND EXTENSION
(1) Clean mating surfaces of transfer case housing
and the rear retainer of any original gasket material.
(2) Install new rear retainer gasket onto the trans-
fer case housing or rear retainer.
(3) Align and install rear retainer on rear case
(Fig. 92).
(4) Apply MopartSilicone Sealer to threads of rear
retainer bolts. Then install retainer bolts finger tight.
(5) Install output bearing on mainshaft and seat it
in rear retainer with suitable size pipe tool (Fig. 93).
Fig. 90 Installing Flange Seal On Front Shaft
1 - FRONT OUTPUT SHAFT
2 - FLANGE SEAL
Fig. 91 Installing Companion Flange On Front Shaft
1 - COMPANION FLANGE
Fig. 92 Rear Retainer Installation
1 - REAR RETAINER
2 - SHIFT RAIL
Fig. 93 Output Bearing Installation
1 - OUTPUT BEARING
2 - PIPE TOOL
21 - 846 TRANSFER CASE - NV231HDBR/BE
TRANSFER CASE - NV231HD (Continued)

(6) Install output bearing retaining ring (Fig. 94).
(7) Tighten rear retainer bolts to 27-34 N´m (20-25
ft. lbs.) torque.
(8) Install new seal in rear extension housing seal
with suitable size installer tool.
(9) 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.
(10) Align and install rear extension on retainer
(Fig. 95).(11) Apply MopartSilicone Sealer to threads of
rear extension housing bolts. Then install and
tighten bolts to 27-34 N´m (20-25 ft. lbs.) torque.
INSTALLATION
(1) Align and seat transfer case on transmission.
Be sure transfer case input gear splines are aligned
with transmission output shaft. Align splines by
rotating transfer case rear output shaft yoke if nec-
essary. Do not install any transfer case attaching
nuts until the transfer case is completely seated
against the transmission.
(2) Install and tighten transfer case attaching
nuts. Tighten nuts to 30-41 N´m (20-30 ft.lbs.).
(3) Install rear crossmember.
(4) Remove jack stand from under transmission.
(5) Align and connect propeller shafts. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - INSTALLATION)
(6) Connect vacuum harness and vent hose.
(7) Connect shift rod to transfer case lever or floor
shift arm. Use channel lock style pliers to press rod
back into lever grommet.
(8) Adjust shift linkage, if necessary.
(9) Fill transfer case with recommended transmis-
sion fluid and install fill plug.
(10) Install skid plate, if equipped. (Refer to 13 -
FRAMES & BUMPERS/FRAME/TRANSFER CASE
SKID PLATE - INSTALLATION)
(11) Lower vehicle
Fig. 94 Output Bearing Retaining Ring Installation
1 - OUTPUT BEARING
2 - RETAINING RING
Fig. 95 Rear Extension Housing Installation
1 - REAR EXTENSION
2 - RETAINER
3 - EXTENSION SEAL
BR/BETRANSFER CASE - NV231HD 21 - 847
TRANSFER CASE - NV231HD (Continued)

SPECIFICATIONS
TRANSFER CASE
TORQUE SPECIFICATIONS
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Plug, Detent 16-24 12-18 -
Bolt, Diff. Case 17-27 15-24 -
Plug, Drain/Fill 40-45 30-40 -
Bolt, Extension Housing 35-46 26-34 -
Bolt, Front Brg. Retainer 16-27 12-24 -
Bolt, Case Half 35-46 26-34 -
Nut, Front Yoke 122-176 90-130 -
Screw, Oil Pump 1.2-1.8 - 12-15
Nut, Range Lever 27-34 20-25 -
Bolt, Rear Retainer 35-46 26-34 -
Nuts, Mounting 30-41 20-30 -
Bolts, U-Joint 19 17 -
Vacuum Switch 20-34 15-25 -
21 - 848 TRANSFER CASE - NV231HDBR/BE
TRANSFER CASE - NV231HD (Continued)