Jeep Wrangler 1999 Electronic Service Manual page 48

3 - 6 DIFFERENTIAL AND DRIVELINE
SERVICE PROCEDURES
DRIVELINE ANGLE MEASUREMENT
PREPARATION
Before measuring universal joint angles, the fol-
lowing must be done;
• Inflate all tires to correct pressure.
• Check the angles in the same loaded or
unloaded condition as when the vibration occurred.
Propeller shaft angles change according to the
amount of load in the vehicle.
• Check the condition of all suspension compo-
nents and verify all fasteners are torqued to specifi-
cations.
• Check the condition of the engine and transmis-
sion mounts and verify all fasteners are torqued to
specifications.
PROPELLER SHAFT ANGLE MEASUREMENT
To accurately check driveline alignment, raise and
support the vehicle at the axles as level as possible.
Allow the wheels and propeller shaft to turn.
(1) Remove any external bearing snap rings, if
equipped, from universal joint so protractor base sits
flat.
(2) Rotate the shaft until transmission/transfer
case output yoke bearing is facing downward.
Always make measurements from front to
rear. Also, be sure to take all measurements
while working from the same side of the vehi-
cle.
(3) Place Inclinometer on yoke bearing (A) parallel
to the shaft (Fig. 9). Center bubble in sight glass and
record measurement.
This measurement will give you the transmis-
sion or Output Yoke Angle (A).
(4) Rotate propeller shaft 90 degrees and place
Inclinometer on yoke bearing parallel to the shaft
(Fig. 10). Center bubble in sight glass and record
measurement. This measurement can also be taken
at the rear end of the shaft.
This measurement will give you the Propeller
Shaft Angle (C).
(5) Subtract smaller figure from larger (C minus
A) to obtain Transmission Output Operating Angle.
(6) Rotate propeller shaft 90 degrees and place
Inclinometer on pinion yoke bearing parallel to the
shaft (Fig. 11). Center bubble in sight glass and
record measurement.
This measurement will give you the pinion
shaft or Input Yoke Angle (B).
Fig. 9 Front (Output) Angle Measurement (A)
Fig. 10 Propeller Shaft Angle Measurement (C)
(7) Subtract smaller figure from larger (C minus
B) to obtain axle Input Operating Angle.
Refer to rules given below and the example in (Fig.
12) for additional information.
• Good cancellation of U–joint operating angles
(within 1°).
• Operating angles less than 3°.
• At least 1/2 of one degree continuous operating
(propeller shaft) angle.
TJ