JEEP XJ 1995 Service And Repair Manual

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
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(11) Remove oil pump and rear case as an assem-
bly (Fig. 5).
(12) Slide oil pickup tube screen out of case pocket.
(13) Remove oil pump and pickup tube as assembly
(Fig. 6).(14) Disconnect screen from pickup tube and re-
move screen (Fig. 7).
(15) Remove pickup tube from oil pump (Fig. 7).
(16) Remove pickup tube O-ring from oil pump
(Fig. 8).
(17) Remove mode spring (Fig. 9).
Fig. 5 Rear Case And Oil Pump Removal
Fig. 6 Oil Pump And Pickup Tube Removal
Fig. 7 Removing Oil Screen And Pickup Tube
Fig. 8 Pickup Tube O-Ring Location
Fig. 9 Mode Spring Removal
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(18) Tap front output shaft upward with rawhide
mallet to free it from shaft bearing.
(19) Remove front output shaft and drive chain
(Fig. 10).
(20) Remove mainshaft, mode fork and shift rail as
assembly d (Fig. 11).
(21) Remove mode fork and shift rail from synchro
sleeve (Fig. 12).
(22) Remove hub snap ring and remove spacer if
equipped (Fig. 13).
(23) Remove sleeve from hub (Fig. 14).
Fig. 10 Front Output Shaft And Drive Chain
Removal
Fig. 11 Removing Mainshaft, Mode Fork And Shift
Rail
Fig. 12 Removing Mode Fork And Rail From Sleeve
Fig. 13 Hub Snap Ring And Spacer Removal
Fig. 14 Removing Sleeve From Hub
JNP231 TRANSFER CASE 21 - 291

(24) Remove hub from mainshaft. On synchro mod-
els, also remove synchro stop ring (Fig. 15).
(25) Remove drive sprocket (Fig. 16).
(26) Slide range fork pin out of shift sector (Fig.
17).
(27) Remove range fork and shift hub (Fig. 18).
(28) Remove range lever from sector shaft.
(29) Remove shift sector (Fig. 19).(30) Remove sector shaft bushing and O-ring (Fig.
20).
Fig. 15 Hub And Stop Ring Removal
Fig. 16 Drive Sprocket Removal/Installation
Fig. 17 Disengaging Range Fork
Fig. 18 Range Fork And Hub Removal/Installation
Fig. 19 Shift Sector Removal/Installation
Fig. 20 Removing/Installing Sector Shaft Bushing
And O-Ring
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(31) Remove shift detent plunger, spring and plug
(Fig. 21). Remove O-ring from plug after removal.
(32) Turn front case over and remove front bearing
retainer bolts (Fig. 22).
(33) Remove front bearing retainer. Position screw-
drivers in retainer slots and lift upward to loosen
and remove retainer (Fig. 23).
(34) Remove input gear snap ring (Fig. 24).
(35) Press input and low range gear assembly out
of input gear bearing with shop press (Fig. 25).
(36) Remove low range gear snap ring (Fig. 26).
(37) Remove retainer, thrust washers and input
gear from low range gear (Fig. 27).
(38) Remove oil seals from rear retainer, rear ex-
tension housing, oil pump feed housing and case
halves.
(39) Remove magnet from pocket in front case.
Fig. 21 Detent Component Removal
Fig. 22 Front Bearing Retainer Bolt Locations
Fig. 23 Removing Front Bearing Retainer
Fig. 24 Removing Input Gear Snap Ring
Fig. 25 Removing Input And Low Range Gear
Assembly
JNP231 TRANSFER CASE 21 - 293

OVERHAUL CLEANING AND INSPECTION
Clean the transfer case components thoroughly
with solvent. Remove all traces of sealer from the
case and retainer seal surfaces.
Clean the oil pickup screen with solvent. Shake ex-
cess solvent from screen and allow it air dry. Use
compressed air to remove solvent residue from all oil
feed passages and channels in the case halves.
Inspect the splines and bearing surfaces on the
both shafts. Replace either shaft as necessary if wear,
or damage is evident.
Check condition of the shift forks, fork pads and
shift rail. Minor scratches/nicks on the rail can be
smoothed with 320/400 grit emery cloth. Replace the
mode fork pads if worn. Replace the range fork if the
pads are worn, missing, or damaged.
On synchro equipped models, inspect the synchro
sleeve, hub, struts, springs, and the stop ring. Re-
place worn, or damaged parts as necessary.
Do not attempt to salvage and reuse snap rings
that were bent, or distorted. It is recommended that
all snap rings be replaced during overhaul.Replace the front yoke nut as it should not be re-
used. Also replace the rubber seal if worn, cut, or
torn.
Inspect the low range annulus gear (Fig. 28).If
the gear is damaged, replace the gear and front
case as an assembly. Do not attempt to remove
the gear.
Inspect the case halves, extension housing and re-
tainers for cracks, porosity, or damaged sealing sur-
faces.
Inspect the drive sprockets and drive chain care-
fully. Replace the sprockets if worn, chipped, or
cracked. Also replace the chain if distorted, binds at
any point, or is stretched.
Replace the oil pump if any pump part is worn or
damaged. Do not disassemble the pump as parts are
not available separately. The pump is only available
as an assembly.
Inspect all of the transfer case bearings for wear,
roughness, pitting, or galling. Replace worn or dam-
aged bearings as outlined in the transfer case assem-
bly procedures.
Clean the sealing (mating) surfaces of the case
halves, retainer and extension with a scraper, a wire
brush and 3M All Purpose cleaning solvent. These
surfaces must be clean in order for the sealer to ad-
here properly.
TRANSFER CASE ASSEMBLY
CAUTION: The bearing bores in various transfer
case components contain oil feed holes. Be sure re-
placement bearings do not block these feed holes.
In addition, the drive sprocket, synchro hub and
sleeve are different for non-synchro and synchro
models. Do not interchange these parts. Do not in-
stall synchro struts or a stop ring in a non-synchro
model; this will cause the drive sprocket to bind on
the shaft and hub.
Fig. 26 Removing Low Range Gear Snap Ring
Fig. 27 Input And Low Range Gear Components
Fig. 28 Low Range Annulus Gear Location
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FRONT CASE ASSEMBLY
(1) Lubricate components with automatic transmis-
sion fluid (or petroleum jelly where indicated) during
assembly.
(2) Remove front output shaft seal from front case
with crowfoot style pry tool (Fig. 29).
(3) Remove snap ring retaining front output shaft
front bearing in case (Fig. 30).
(4) Tap old front output shaft bearing out of front
case with plastic mallet. Install new bearing with
Tool Handle C-4171 and Installer Tool 5064 (Fig. 31).
(5) Secure front output shaft bearing in front case
with new snap ring (Fig. 30).
(6) Install new front output shaft seal in front case
with suitable size socket or installer tool.
(7) If front output shaft rear bearing is to be re-
placed, install new bearing as follows:
(a) Remove bearing from rear case with Bearing
Remover MD-998346 and two suitable size
wrenches (Fig. 32).(b) Seat new bearing in rear case with Tool Han-
dle C-4171 and Bearing Installer 5063 (Fig. 33).
Fig. 29 Front Output Shaft Oil Seal Removal
Fig. 30 Removing/Installing Front Output Shaft
Bearing Snap Ring
Fig. 31 Installing Front Output Shaft Front Bearing
In Case
Fig. 32 Front Output Shaft Rear Bearing Removal
Fig. 33 Front Output Shaft Rear Bearing Installation
JNP231 TRANSFER CASE 21 - 295

(8) Remove input gear bearing from front case
with Tool Handle C-4171 and Tool C-4210, 7828, or
5062. Use tool that is best fit in bearing (Fig. 34).
(9) Turn front case over.
(10) Start bearing in case by hand. Then seat bear-
ing with Tools C-4171 and C-4210, or 7828 until snap
ring seats against case surface (Fig. 35).
INPUT AND LOW RANGE GEAR ASSEMBLY
AND INSTALLATION
(1) Remove mainshaft pilot bearing from input
gear with Tool MD-998346, or similar tool as follows:
(a) Turn puller tool bolt until jaws retract
enough to fit into bearing (Fig. 36).
(b) Insert puller bolt and jaws into bearing. Then
turn puller bolt clockwise so ramp on bolt spreads
jaws forcing them under bearing (Fig. 37).
Fig. 34 Input Gear Bearing Removal
Fig. 35 Input Gear Bearing Installation
Fig. 36 Puller Jaws In Retracted Position
Fig. 37 Puller Bolt And Jaws Seated Under Needle
Bearing
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(c) Install puller bridge over puller bolt (Fig. 38).
Then install flat washer and nut on bolt.
(d) Hold puller bridge from turning by hand or
with locking pliers. Then tighten nut on puller bolt
in clockwise direction to draw bearing out of input
gear (Fig. 39).
(2) Install new needle bearing in input gear with
Tool Handle C-4171 and Installer 5065 (Fig. 40).
(3) Lubricate and install thrust washers, input
gear and retainer in low range gear (Fig. 41). Then
install retainer snap ring.Be sure snap ring is
fully seated before proceeding.
(4) Align and install input/low range gear assembly in
case. Use hammer handle to tap low range gear into an-
nulus and input gear into bearing if necessary.
(5) Install input gear snap ring (Fig. 42).
(6) Install new oil seal in input bearing retainer
with suitable size installer tool (Fig. 43).
(7) Apply 3 mm (1/8 in.) wide bead of Mopar Gas-
Fig. 38 Installing Puller Bridge
Fig. 39 Removing Mainshaft Pilot Bearing From
Input Gear
Fig. 40 Installing Mainshaft Pilot Bearing In Input
Gear
Fig. 41 Input And Low Range Gear Components
Fig. 42 Installing Input Gear Snap Ring
JNP231 TRANSFER CASE 21 - 297

ket Maker, silicone adhesive/sealer, or Loctite 518 to
front bearing retainer seal surface (Fig. 44).
(8) Align oil channel in retainer with oil feed hole
in case (Fig. 45).
(9) Install input (front) bearing retainer on front
case (Fig. 46). Tighten retainer bolts to 21 Nzm (16 ft.
lbs.) torque.
SHIFT SECTOR, RANGE FORK AND SLEEVE
INSTALLATION
(1) Install new sector shaft O-ring and retainer
bushing (Fig. 47).
Fig. 43 Installing Input Bearing Retainer Oil Seal
Fig. 44 Applying Sealer Bead To Bearing Retainer
Fig. 45 Aligning Retainer Oil Channel With Feed
Hole In Case
Fig. 46 Bearing Retainer Installation
Fig. 47 Installing Sector O-Ring And Retainer
Bushing
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