transmission DODGE RAM 2001 Service Repair Manual

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)

Condition Possible Cause Correction
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.
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 vacuum harness at
transfer case switch.
(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) Remove rear crossmember.
(9) Mark front and rear propeller shafts for assem-
bly reference.(10) Remove front and rear propeller shafts. (Refer
to 3 - DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - REMOVAL)
(11) Support transfer case with suitable jack.
Secure transfer case to jack with safety chains.
(12) Remove nuts attaching transfer case to trans-
mission.
(13) Move transfer case assembly rearward until
free of transmission output shaft.
(14) 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.
21 - 822 TRANSFER CASE - NV231HDBR/BE
TRANSFER CASE - NV231HD (Continued)

(11) Remove seal from oil pump with suitable pry
tool.
(12) Install new seal in oil pump with Installer
7888 (Fig. 51).
(13) Remove input gear pilot bearing by inserting
a suitably sized drift into the splined end of the input
gear and driving the bearing out with the drift and a
hammer (Fig. 52).
(14) Install new pilot bearing with Plug C-293-3.(15) Remove the output shaft rear bearing with
the screw and jaws from Remover L-4454 and Cup
8148 (Fig. 53).
(16) Install new bearing with Tool Handle C-4171
and Installer 5066 (Fig. 54). The bearing bore is
chamfered at the top. Install the bearing so it is
flush with the lower edge of this chamfer (Fig. 55).
INPUT AND PLANETARY GEAR
(1) Lubricate gears and thrust washers (Fig. 56)
with recommended transmission fluid.
(2) Install first thrust washer in low range gear
(Fig. 56). Be sure washer tabs are properly aligned in
gear notches.
(3) Install input gear in low range gear. Be sure
input gear is fully seated.
(4) Install remaining thrust washer in low range
gear and on top of input gear. Be sure washer tabs
are properly aligned in gear notches.
(5) Install retainer on input gear and install snap-
ring.
(6) Align and install low range/input gear assem-
bly in front case (Fig. 57). Be sure low range gear
pinions are engaged in annulus gear and that input
gear shaft is fully seated in front bearing.
Fig. 51 Install Oil Pump Seal
1 - HOUSING SEAL
2 - SPECIAL TOOL 7888
3 - OIL PUMP FEED HOUSING
Fig. 52 Remove Input Gear Pilot Bearing
1 - DRIFT
2 - INPUT GEAR
Fig. 53 Output Shaft Rear Bearing Removal
1 - REAR CASE
2 - SPECIAL TOOL L-4454-1 AND L-4454-3
3 - SPECIAL TOOL 8148
21 - 836 TRANSFER CASE - NV231HDBR/BE
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)

(6) Install synchro hub retaining ring (Fig. 66). Be
sure ring is fully seated before proceeding.
(7) Install sliding clutch (sleeve) on synchro hub
(Fig. 67).
CAUTION: The sliding clutch must be correctly
positioned to ensure proper shifting. Position the
clutch on the hub so a clutch spline is centeredover each strut as shown (Fig. 68). If the clutch is
installed so a gap between splines is aligned with
one or more struts, gear clash will result.
(8) Support front case on wood blocks so case inte-
rior is facing up. Place blocks between mounting
studs on forward surface of case. Be sure blocks will
not interfere with input gear installation.
(9) Lubricate mainshaft components with trans-
mission fluid.
(10) Lubricate sector shaft with transmission fluid
and install shift sector in case (Fig. 69). Position slot
in sector so it will be aligned with shift fork pin
when shift forks are installed.
(11) Assemble and install range fork and hub (Fig.
70). 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.
Fig. 66 Synchro Hub Retaining Ring Installation
1 - SNAP-RING PLIERS
2 - SYNCHRONIZER HUB
3 - HUB RETAINING RING
Fig. 67 Sliding Clutch Installation
1 - SLIDING CLUTCH
2 - SYNCHRONIZER HUB
Fig. 68 Correct Alignment Of Struts And Sliding
Clutch
1 - SLEEVE TOOTH ALIGNED WITH STRUT
2 - STRUT
3 - SLEEVE TOOTHNOTALIGNED WITH STRUT
4 - STRUT
21 - 840 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)

(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)

FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL
The fill and drain plugs are both in the rear case
(Fig. 97).
(1) Raise vehicle.
(2) Position drain pan under transfer case.
(3) Remove drain and fill plugs and drain lubri-
cant completely.
(4) Install drain plug. Tighten plug to 41-54 N´m
(30-40 ft. lbs.).
(5) Remove drain pan.
(6) Fill transfer case to bottom edge of fill plug
opening with MopartATF +4, type 9602, Automatic
Transmission fluid.
(7) Install and tighten fill plug to 41-54 N´m
(30-40 ft. lbs.).
(8) Lower vehicle.
FRONT OUTPUT SHAFT SEAL
REMOVAL
(1) Shift transfer case into NEUTRAL.
(2) Raise vehicle.
(3) Remove front propeller shaft. (Refer to 3 - DIF-
FERENTIAL & DRIVELINE/PROPELLER SHAFT/
PROPELLER SHAFT - REMOVAL)
(4) Remove companion flange nut (Fig. 98).
(5) Remove companion flange from output shaft.
Use a suitable puller if flange can not be removed by
hand.(6) Remove companion flange rubber seal from
front output shaft (Fig. 99).
(7) Remove seal from front case with pry tool (Fig.
100).
Fig. 98 Removing Companion Flange Nut
1 - COMPANION FLANGE
2 - SOCKET
Fig. 99 Companion Flange Seal Removal
1 - FLANGE SEAL
Fig. 100 Remove Front Output Shaft Seal
1 - OUTPUT SHAFT SEAL
2 - PRYBAR
Fig. 97 Fill/Drain Plug and I.D. Tag Location - Typical
1 - I.D. TAG
2 - FILL PLUG
3 - DRAIN PLUG
BR/BETRANSFER CASE - NV231HD 21 - 851

INSTALLATION
(1) Install new front output seal in front case with
Installer Tool 8143-A as follows:
(a) Place new seal on tool. Garter spring on seal
goes toward interior of case.
(b) Start seal in bore with light taps from ham-
mer (Fig. 101). Once seal is started, continue tap-
ping seal into bore until installer tool seats against
case.
(2) Install companion flange seal on front shaft
(Fig. 102).
(3) Install companion flange on front shaft (Fig.
103). Then install and tighten flange nut to 176-271
N´m (130-200 ft. lbs.) torque.(4) Install propeller shaft. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/PROPELLER SHAFT/PRO-
PELLER SHAFT - INSTALLATION)
SHIFT LEVER
REMOVAL
(1) Shift transfer case into 2H.
(2) Remove transfer case shifter knob cap.
(3) Remove nut holding shifter knob to shift lever.
(4) Remove shifter knob.
(5) Remove the shift boot from the shifter bezel.
(6) Remove the bolts securing the shifter mecha-
nism to the floor pan along the driver's side of the
transmission tunnel (Fig. 104).
(7) Raise and support the vehicle.
(8) 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.
(9) Remove the nuts holding the shifter mecha-
nism to the underside of the floor pan.
(10) Separate shift lever mechanism from the vehi-
cle.
Fig. 101 Front Output Seal Installation
1 - INSTALLER 8143-A
2 - TRANSFER CASE
Fig. 102 Installing Flange Seal On Front Shaft
1 - FRONT OUTPUT SHAFT
2 - FLANGE SEAL
Fig. 103 Installing Companion Flange On Front
Shaft
1 - COMPANION FLANGE
21 - 852 TRANSFER CASE - NV231HDBR/BE
FRONT OUTPUT SHAFT SEAL (Continued)

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 vehiclemust 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.
21 - 856 TRANSFER CASE - NV241LDBR/BE
TRANSFER CASE - NV241LD (Continued)