1995 JEEP YJ service

NP231 TRANSFER CASE
INDEX
page page
General Information....................... 283
Overhaul Cleaning and Inspection............ 294
Shift Lever Installation (XJ)................. 286
Shift Lever Installation (YJ)................. 286
Shift Lever Removal (XJ)................... 286
Shift Lever Removal (YJ)................... 286
Shift Linkage Adjustment................... 286Speedometer Service..................... 287
Transfer Case Assembly................... 294
Transfer Case Disassembly and Overhaul...... 289
Transfer Case Identification................. 284
Transfer Case Installation.................. 288
Transfer Case Lubricant and Fill Level......... 284
Transfer Case Removal.................... 287
GENERAL INFORMATION
The NP231 is a part-time transfer case with a low
range reduction gear system (Fig. 1). The NP231 has
three operating ranges plus a Neutral position. A low
range system provides a reduction ratio for increased
low speed torque capability.The NP231 is the Command Trac transfer case. It
is used in XJ and YJ models. Two versions are used.
One version retains the synchronizer components
used in previous models. A newly introduced version
is not equipped with synchro components.
Fig. 1 NP231 Transfer Case
JNP231 TRANSFER CASE 21 - 283

NP231 SERVICE DIAGNOSIS
JNP231 TRANSFER CASE 21 - 285

SHIFT LINKAGE ADJUSTMENT
(1) Shift transfer case into 4L position.
(2) Raise vehicle.
(3) Loosen lock bolt on adjusting trunnion (Figs. 3
and 4).
4) Be sure linkage rod slides freely in trunnion.
Clean rod and apply spray lube if necessary.
(5) Verify that transfer case range lever is fully en-
gaged in 4L position.
(6) Tighten adjusting trunnion lock bolt.
(7) Lower vehicle.
SHIFT LEVER REMOVAL (XJ)
(1) Shift transfer case into 4L.
(2) Raise vehicle.
(3) Loosen adjusting trunnion locknut and slide
shift rod out of trunnion (Fig. 4). If rod lacks enough
travel to come out of trunnion, push trunnion out of
torque shaft.
(4) Lower vehicle.
(5) Remove console. Refer to park brake section in
Group 5 for procedures.
(6) Remove screws attaching lever assembly to
floorpan and remove assembly and shift rod (if left
attached).
SHIFT LEVER INSTALLATION (XJ)
(1) If shift rod was not removed from lever assem-
bly, work rod down through floorpan opening. Then
position lever assembly on floorpan and install as-
sembly attaching screws.
(2) Install console.
(3) Raise vehicle.
(4) Connect trunnion to torque shaft arm. Or, slide
shift rod into trunnion on range lever. Be sure shift
rod slides freely in trunnion.
(5) Verify that range lever is in 4L position. Then
tighten trunnion lock bolt.(6) Lower vehicle and check transfer case shift op-
eration.
SHIFT LEVER REMOVAL (YJ)
(1) Shift transfer case into neutral.
(2) Remove shift lever knob and retaining nut.
Then remove shift lever boot and bezel.
(3) Raise vehicle
(4) Loosen lock bolt in adjusting trunnion and slide
shift rod out of trunnion (Fig. 3).
(5) Remove bolts/nuts attaching bracket and brace
assembly to transmission (Fig. 5).
(6) Remove shift lever and bracket as assembly.
(7) YJ shift lever assembly is serviceable. If any
assembly part must be replaced, remove pivot bolt,
lever pin E-clip, and lever pin and spring. Then dis-
assemble and replace necessary part (Fig. 6).
SHIFT LEVER INSTALLATION (YJ)
(1) Assemble lever components, if necessary. Lube
pivot bolt and pin with Mopar multi-mileage grease
before installation.
(2) Work shift lever upward into vehicle interior.
Then position lever and bracket assembly on trans-
mission and install attaching bolts/nuts.
(3) Place transfer case range lever in 4L position.
Then slide shift rod into trunnion and tighten lock
bolt.
Fig. 3 Adjusting Trunnion And Lock Bolt (YJ)
Fig. 4 Shift Linkage (XJ)
21 - 286 NP231 TRANSFER CASEJ

(4) Lower vehicle.
(5) Install shift lever bezel and boot (Fig. 7). Then
install retaining nut and shift knob on lever.
SPEEDOMETER SERVICE
Speedometer service is covered in the 30RH/32RH,
or AW-4 automatic transmission sections in this
group. Refer to the appropriate section as needed.
TRANSFER CASE REMOVAL
(1) Shift transfer case into Neutral.
(2) Raise vehicle.
(3) Drain transfer case lubricant.
(4) Mark front and rear propeller shaft yokes for
alignment reference.
(5) Support transmission with jack stand.
(6) Remove rear crossmember, or skid plate.
(7) Disconnect front/rear propeller shafts at trans-
fer case.
(8) Disconnect vehicle speed sensor wires.
(9) Disconnect transfer case linkage rod from range
lever.
(10) Disconnect transfer case vent hose, and indi-
cator or vacuum switch harness.
(11) Support transfer case with transmission jack.
(12) Remove nuts attaching transfer case to trans-
mission.
(13) Secure transfer case to jack with chains.
Fig. 5 Shift Linkage Mounting (YJ)
Fig. 6 Shift Linkage (YJ)
JNP231 TRANSFER CASE 21 - 287

TRANSFER CASE DISASSEMBLY AND OVERHAUL
Two versions of the NP231 are used in current
models. One version retains the synchronizer
components used in previous years. A newly intro-
duced version does not have synchro components.
The non-synchro version is not equipped with a
synchro gear, struts, springs, or stop ring. During
overhaul, note which version is being serviced
and order needed parts accordingly.
(1) Remove fill and drain plugs. Also remove speed-
ometer adapter and pinion if not previously removed.
(2) Remove front yoke. Discard yoke seal washer
and nut. They should not be reused.
(3) Move transfer case range lever rearward to 4L
position.
(4) Remove extension housing attaching bolts.
(5) Tap extension housing in clockwise direction to
break sealer bead and remove housing (Fig. 1).
CAUTION: To avoid damaging the sealing surfaces
of the extension housing and rear retainer, do not
pry or wedge the housing off the retainer.
(6) Remove rear bearing snap ring (Fig. 2).
(7) Remove rear retainer attaching bolts.
(8) Remove rear retainer. Position screwdriver un-
der each tab on retainer housing (Fig. 3). Then care-
fully pry retainer upward and off rear case.
CAUTION: Do not pry against the sealing surfaces
of the retainer or rear case. The surfaces could be
damaged.
(9) Remove bolts attaching rear case to front case.
Retain bolts and washers.
(10) Separate rear case from front case (Fig. 4) Insert
screwdrivers into slots cast in case ends. Then gently
pry upward to break sealer bead and loosen rear case.
CAUTION: Do not pry against the sealing surfaces of
the retainer or rear case. The surfaces could be dam-
aged.
Fig. 1 Extension Housing Removal
Fig. 2 Rear Bearing Snap Ring Removal
Fig. 3 Rear Retainer Removal
Fig. 4 Loosening Rear Case
JNP231 TRANSFER CASE 21 - 289

NP242 TRANSFER CASE
INDEX
page page
General Information....................... 307
Operating Ranges........................ 307
Overhaul Cleaning and Inspection............ 318
Recommended Lubricant/Capacity/Fill Level..... 307
Shift Lever Installation (XJ)................. 309
Shift Lever Removal (XJ)................... 309
Shift Linkage Adjustment................... 309
Shift Mechanism......................... 307Speedometer Service..................... 309
Transfer Case Assembly................... 319
Transfer Case Changes.................... 307
Transfer Case Disassembly and Overhaul...... 310
Transfer Case Identification................. 307
Transfer Case Installation.................. 309
Transfer Case Removal.................... 309
GENERAL INFORMATION
The NP242 is a full and part-time transfer case
(Fig. 1). It provides full time 2-wheel, or 4-wheel
drive operation. The NP242 is used in XJ models.
A differential in the transfer case is used to control
torque transfer to the front and rear axles. A low
range gear provides increased low speed torque capa-
bility for off road operation. The low range provides a
2.72:1 reduction ratio.
OPERATING RANGES
NP242 operating ranges are 2WD (2-wheel drive),
4x4 part-time, 4x4 full time, and 4 Lo.
The 2WD and 4x4 full time ranges can be used at
any time and on any road surface.
The 4x4 part-time and 4 Lo ranges are for off road use
only. The only time these ranges can be used on hard sur-
face roads, is when the surface is covered with snow and
ice.
SHIFT MECHANISM
Transfer case operating ranges are selected with a floor
mounted shift lever. The shift lever is connected to the trans-fer case range lever by an adjustable linkage rod. Range po-
sitions are marked on the shift knob or shifter bezel plate.
TRANSFER CASE IDENTIFICATION
A circular I.D. tag is attached to the rear case of
each NP242 transfer case (Fig. 2). 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. For example, a serial number of
1-10-94 would represent January 10, 1994.
RECOMMENDED LUBRICANT/CAPACITY/FILL LEVEL
Mopar Dexron II is the recommended fluid for the
NP242 transfer case. Approximate dry fill lubricant
capacity is 1.4 liters (1.48 qts.).
Correct transfer case lubricant level is to the bot-
tom edge of the fill plug hole.
TRANSFER CASE CHANGES
The only service change for 1995 involves the front
output shaft seal which is new. The new seal does
not have the flange used on prior seals and changes
seal installation. The new seal must be seated below
the edge of the seal bore in the front case. Refer to
the overhaul information for seal installation.
Fig. 1 NP242 Transfer Case
Fig. 2 Transfer Case I.D. Tag
JNP242 TRANSFER CASE 21 - 307

NP242 SERVICE DIAGNOSIS
21 - 308 NP242 TRANSFER CASEJ

SHIFT LINKAGE ADJUSTMENT
(1) Shift transfer case into 4L position.
(2) Raise vehicle.
(3) Loosen lock bolt on adjusting trunnion (Fig. 3).
4) Verify that linkage rod slides freely in trunnion.
Clean rod and apply spray lube if necessary.
(5) Verify that transfer case range lever is fully en-
gaged in 4L position.
(6) Tighten adjusting trunnion lock bolt.
(7) Lower vehicle.
(8) Verify proper shift operation.
SHIFT LEVER REMOVAL (XJ)
(1) Shift transfer case into 4L.
(2) Raise vehicle.
(3) Loosen adjusting trunnion locknut and slide
shift rod out of trunnion (Fig. 4). If rod lacks enough
travel to come out of trunnion, push trunnion out of
torque shaft.
(4) Lower vehicle.
(5) Remove console. Refer to park brake section in
Group 5 for procedures.
(6) Remove screws attaching lever assembly to floor-
pan and remove assembly and shift rod (if left attached).
SHIFT LEVER INSTALLATION (XJ)
(1) If shift rod was not removed from lever assem-
bly, work rod down through floorpan opening. Then
position lever assembly on floorpan and install as-
sembly attaching screws.
(2) Install console.
(3) Raise vehicle.
(4) Connect trunnion to torque shaft arm. Or, slide
shift rod into trunnion on range lever.
(5) Tighten trunnion lock bolt.
(6) Lower vehicle.
(7) Lower vehicle.
(8) Remove shift lever spacer and install bezel.
SPEEDOMETER SERVICE
Speedometer service procedures are covered in the
automatic transmission sections within Group 21.
Refer to these sections when necessary.
TRANSFER CASE REMOVAL
(1) Shift transfer case into Neutral.
(2) Raise vehicle.
(3) Drain transfer case lubricant.
(4) Mark front and rear propeller shaft yokes for
alignment reference.
(5) Place support stand under transmission.
(6) Remove rear crossmember.
(7) Disconnect front/rear propeller shafts at trans-
fer case.
(8) Disconnect vehicle speed sensor wires and re-
move sensor and adapter assembly if necessary.
(9) Disconnect shift rod from transfer case range
lever.
(10) Disconnect transfer case vent hoses and elec-
trical switch connector.
(11) Support transfer case with transmission jack.
(12) Remove bolts attaching transfer case to trans-
mission.
(13) Secure transfer case to jack with chains.
(14) Pull transfer case and jack rearward to disen-
gage transfer case.
(15) Remove transfer case from under vehicle.
(16) If transfer case was removed for overhaul, re-
move damper from rear retainer.
TRANSFER CASE INSTALLATION
(1) Install damper on transfer case rear retainer, if
equipped (Fig. 4). Tighten damper attaching nuts to
54 Nzm (40 ft. lbs.) torque.
(2) Mount transfer case on transmission jack. Se-
cure transfer case to jack with safety chains.
(3) Position transfer case under vehicle.
(4) Align transfer case and transmission shafts and
slide transfer case onto transmission.
(5) Install and tighten transfer case attaching nuts
to 35 Nzm (26 ft. lbs.) torque.
Fig. 3 Shift Linkage (XJ)
JNP242 TRANSFER CASE 21 - 309