Front Axle Shift Motor; Vacuum Control System; Vacuum System Diagnosis; Shift Motor Function Test - Jeep 1987 Wrangler Workshop Manual

STEERING AND FRONT AXLE
FRONT AXLE SHIFT MOTOR
S E E
I.S.
N
O
T
E
S
VACUUM CONTROL SYSTEi
The front axle shift motor disconnects the right-
front axle shaft for two-wheel drive operation.
The shift motor is vacuum operated.
The shift motor is mounted in the motor housing
located on the right-front axle tube.
The vacuum control system consists of:
• The axle mounted shift motor (A).
• The control switch (B) on the transfer case.
• The four-wheel drive indicator switch (C).
• An air vent filter (D).
• Two check valves (E).
B
84856A
f ACUUM SYSTEM DIAGNOSIS
Diagnosis procedures for the vacuum system
are outlined in diagnosis charts in Chapter D -
Gearboxes. Refer to the Transfer C a s e section
in this chapter. However, shift motor function
testing is outlined in the following procedure.
SHIFT MOTOR FUNCTION TEST
Disconnect the vacuum harness from the shift
motor (A).
Connect a hand operated vacuum pump to the
shift motor front port (B).
Apply 51 kPa (15 in. Hg.) to the motor through
port (B) and rotate the right-front wheel to
disengage the axle shaft.
The shift motor should maintain applied vacuum
for a minimum of 30 seconds. Replace the motor
if it does not hold vacuum for the specified time.
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G-136