1988 JEEP CHEROKEE Service Repair Manual

Fig. 21: Alternator W/Serpentine Belt: 4.2L Grand Wagoneer
(California)
Courtesy of Chrysler Motors

Fig. 22: Alternator, A/C, P/S W/Serpentine Belt: 4.2L Grand Wagoneer
Courtesy of Chrysler Motors
Fig. 23: Alternator, A/C, Air Pump & P/S: 5.9L Grand Wagoneer
Courtesy of Chrysler Motors

Fig. 24: Alternator, Air Pump & P/S: 5.9L Grand Wagoneer
Courtesy of Chrysler Motors
BELT TENSION TABLE









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Application New Belt Used Belt
(1) ( 1)
All Engines ............... 180-200 (82 - 90) ........ 140-160 (63-72\
)
( 1) - Tension in Lbs. (Kg) Using Strand Tension Gauge









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DRIV E S H AFT A LIG NM EN T

1988 J e ep C hero ke e
1988 Drive Shafts Alignment
DESCRIPTION
Drive shafts are balanced, one-piece, tubular shafts with
universal joints at each end. Number used in vehicle varies: one
shaft, 2 shafts with a center bearing, or 3 shafts. Three shafts are
used in many 4WD applications. Location of slip joints varies with
model and manufacturer. See Fig. 1.
Fig. 1: View of 5 Commonly Used Drive Shaft Combinations
Many 4WD models use 3 drive shafts.
INSPECTION

Vibration can come from many sources. Before overhauling
driveline, check other sources of possible vibration as follows:
* Tires and wheels - Check tire inflation and wheel balance.
Check for foreign objects in tread, damaged tread, mismatched
tread patterns or incorrect tire size.
* Center Bearing - Tighten drive shaft center bearing
mounting bolts. If bearing insulator is deteriorated or
oil-soaked, replace it.
* Engine & Transmission Mountings - Tighten mounting bolts.
If mountings are deteriorated, replace them.
* Drive Shaft - Check drive shaft for damage or dents that
could affect balance. Check for undercoating adhering to
shafts. If present, clean shafts thoroughly.
* Universal Joints - Check for foreign material stuck in
joints. Check for loose bolts and worn bearings.
ADJUSTMENTS
DRIVE SHAFT PHASING
One-Piece Shafts
Check that flanges on either end of drive shaft are in same
plane. Often there are arrows on slip joint and drive shaft to aid in
alignment. See Fig. 2. If flanges are not in same plane, disassemble
universal joint and align.
Fig. 2: Slip Joint Alignment Arrows
Align arrows for proper shaft phasing.
2-Piece Shafts
1) All General Motors models with 32 splines use keys on
spline and slip joint, which can only mate in correct position. On
most models with 2-piece shafts, proper phasing is accomplished by
keys on spline and slip joint.

2) On models with 2-piece shafts, rotate transmission yoke
until trunnion is in horizontal plane. Install front drive shaft with
"U" joint trunnion in vertical plane. Connect bearing support to
crossmember.
3) Ensure that front face of bearing support is perpendicular
(90 degrees) to centerline of drive shaft. Install rear drive shaft
with "U" joint trunnion of slip joint in vertical plane.
4) Set differential pinion yoke trunnion in vertical plane.
Connect rear drive shaft to pinion yoke. If 2-piece shaft is correctly
installed, centerline of trunnions at each end of individual shafts
will be parallel. See Fig. 3.
Fig. 3: Phase Alignment Of 2-Piece Drive Shafts
Trunnion yoke ears on each shaft must be parallel.
DRIVE SHAFT BALANCE TEST
1) Drive shaft imbalance may often be cured by disconnecting
shaft and rotating it 180 degrees in relation to other components.
Test by raising rear wheels off ground, and turning shaft with engine.
NOTE: DO NOT run engine without ram airflow across radiator for
prolonged periods, as overheating of engine or transmission
may occur.
2) On most models, balance testing may be done by marking
shaft in 4 positions, 90 degrees apart. Place marks approximately 6"
forward of weld, at rear end of shaft. Number marks one through 4.
3) Place screw-type hose clamp so clamp head is in number one
position, and rotate shaft with engine. If there is little or no
change, move clamp head to No. 2 position, and repeat test.
4) Continue procedure until vibration is at lowest level. If
no difference is noted with clamp head moved to all 4 positions,
vibrations may not be drive shaft imbalance.
5) If vibration is lessened but not completely gone, place 2
clamps at that point, and run test again. Combined weight of clamps in
one position may increase vibration. If so, rotate clamps 1/2" apart,
above and below best position, and repeat test.
6) Continue to rotate clamps as necessary, until vibration is
at lowest point. If vibration level is still unacceptable, leave rear
clamp(s) in position and repeat procedure at front end of drive shaft.\
If vibration can be eliminated or reduced to acceptable levels using
this test procedure, send drive shaft out to be balanced.

Fig. 4: Drive Shaft Phase Alignment
Align drive shaft and slip joint trunnions in same plane.
FLANGE ALIGNMENT & RUNOUT
1) All flanges must be perpendicular in both vertical and
horizontal planes to engine crankshaft. Only exception is "broken
back" type driveline, which has flanges that are not perpendicular in
vertical plane. See Fig. 5.
Fig. 5: Typical "Broken Back" Type Drive Shaft Alignment
Angle "A" equals angle "B".
2) With nonparallel or "broken back" type installation,
working angles of universal joints of given drive shaft are equal.
Angle "A" = angle "B".
3) This is calculated as follows: angle of output shaft
centerline is subtracted from angle of drive shaft. Difference should
equal angle of drive shaft subtracted from pinion shaft angle.
4) Parallel type joints maintain constant velocity between
output shaft and pinion shaft. Vibration is minimized and component
life maximized when universal joints are parallel.

Fig. 6: Aligning One-Piece Drive Shaft
Yokes must be parallel.
5) Using dial indicator, measure runout of transmission
flange, center bearing flange and pinion flange. If runout exceeds .
003-.005" (.08-.13 mm), replace flange.
6) If dial indicator cannot be used, push rod with snug fit
through flange bearing bore. See if it aligns with opposite flange
bore. If not, replace flange.
7) Rotate transmission flange until it is vertical, measuring
from side. Check center bearing and pinion flanges. They cannot be
more than one degree off vertical. See DRIVE SHAFT PHASING in this
article.
Fig. 7: Vertical Alignment of Drive Shaft
Flanges in pairs should be parallel.
8) Rotate transmission flange until it is vertical, measured
from side. Measure angle from end and record it. Check all other
flanges for same angle. They must be within 1/2 degree of each other.
Adjust as required.