Bedrck47
Full Access Members
check your vacuum and components
Possible Issue with ESOF
- Thread starter Joseph
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Joseph
Member
2wd vacuum feels weaker than 4wd, could this be the problem?
Bedrck47
Full Access Members
I am not totally familiar with the vacuum system on the 97. From what I have read it appears that you have a component leaking and loosing vacuum which causes the axel to engage.(slow loss of vacuum) Have copied some information for you. Hopefully someone with more experience will chime in with better advice
PINPOINT TEST A: FRONT AXLE WILL NOT ENGAGE
TEST CONDITIONS TEST DETAILS/RESULTS/ACTIONS
A1 TEST THE SHIFT MOTOR OPERATION
Remove the shift motor cover to the transmission.
Remove the vacuum hose from the outboard shift motor port.
Connect the Vacuum Pump to the outboard shift motor port.
NOTE: If any vacuum leakage is observed while applying vacuum to the outboard shift motor port, REPLACE the vacuum motor.
Apply more than 33.6 kPa (10 in-HG) vacuum while observing the shift lever.
Does the shift lever move freely towards the shift motor?
YES
GO to A2 .
NO
If the vacuum bleeds off, REPLACE the shift motor.
If the vacuum is held, REPAIR the front axle. REFER to Section 205-03 . TEST the system for normal operation.
A2 CHECK THE FRONT AXLE
With vacuum applied to the outboard shift motor port, rotate one of the front axles and observe the other.
Do the axles rotate in one direction?
YES
INSPECT the vacuum hoses for leaks, kinks, etc. REPAIR as necessary. If OK, REFER to Section 308-07A . TEST the system for normal operation.
NO
REPAIR the front axle; REFER to Section 205-03 . TEST the system for normal operation.
PINPOINT TEST B: FRONT AXLE WILL NOT DISENGAGE
TEST CONDITIONS TEST DETAILS/RESULTS/ACTIONS
B1 TEST THE SHIFT MOTOR OPERATION
Remove the shift motor cover to the transmission.
Remove the vacuum hose from the inboard shift motor port.
Connect the Vacuum Pump to the inboard shift motor port.
NOTE: If any vacuum leakage is observed while applying vacuum to the inboard shift motor port, REPLACE the vacuum motor.
Apply more than 33.6 kPa (10 in-HG) vacuum while observing the shift lever.
Does the shift lever move freely away from the shift motor?
YES
GO to B2 .
NO
If the vacuum bleeds off, REPLACE the shift motor.
If the vacuum is held, REPAIR the front axle. REFER to Section 205-03 . TEST the system for normal operation.
B2 CHECK THE FRONT AXLE
With vacuum applied to the inboard shift motor port, rotate one of the front axles and observe the other.
Do the axles turn free of each other?
YES
INSPECT the vacuum hoses for leaks, kinks, etc. REPAIR as necessary. If OK, REFER to Section 308-07A . TEST the system for normal operation.
NO
REPAIR the front axle; REFER to Section 205-03 . TEST the system for normal operation.
PINPOINT TEST A: FRONT AXLE WILL NOT ENGAGE
TEST CONDITIONS TEST DETAILS/RESULTS/ACTIONS
A1 TEST THE SHIFT MOTOR OPERATION
Remove the shift motor cover to the transmission.
Remove the vacuum hose from the outboard shift motor port.
Connect the Vacuum Pump to the outboard shift motor port.
NOTE: If any vacuum leakage is observed while applying vacuum to the outboard shift motor port, REPLACE the vacuum motor.
Apply more than 33.6 kPa (10 in-HG) vacuum while observing the shift lever.
Does the shift lever move freely towards the shift motor?
YES
GO to A2 .
NO
If the vacuum bleeds off, REPLACE the shift motor.
If the vacuum is held, REPAIR the front axle. REFER to Section 205-03 . TEST the system for normal operation.
A2 CHECK THE FRONT AXLE
With vacuum applied to the outboard shift motor port, rotate one of the front axles and observe the other.
Do the axles rotate in one direction?
YES
INSPECT the vacuum hoses for leaks, kinks, etc. REPAIR as necessary. If OK, REFER to Section 308-07A . TEST the system for normal operation.
NO
REPAIR the front axle; REFER to Section 205-03 . TEST the system for normal operation.
PINPOINT TEST B: FRONT AXLE WILL NOT DISENGAGE
TEST CONDITIONS TEST DETAILS/RESULTS/ACTIONS
B1 TEST THE SHIFT MOTOR OPERATION
Remove the shift motor cover to the transmission.
Remove the vacuum hose from the inboard shift motor port.
Connect the Vacuum Pump to the inboard shift motor port.
NOTE: If any vacuum leakage is observed while applying vacuum to the inboard shift motor port, REPLACE the vacuum motor.
Apply more than 33.6 kPa (10 in-HG) vacuum while observing the shift lever.
Does the shift lever move freely away from the shift motor?
YES
GO to B2 .
NO
If the vacuum bleeds off, REPLACE the shift motor.
If the vacuum is held, REPAIR the front axle. REFER to Section 205-03 . TEST the system for normal operation.
B2 CHECK THE FRONT AXLE
With vacuum applied to the inboard shift motor port, rotate one of the front axles and observe the other.
Do the axles turn free of each other?
YES
INSPECT the vacuum hoses for leaks, kinks, etc. REPAIR as necessary. If OK, REFER to Section 308-07A . TEST the system for normal operation.
NO
REPAIR the front axle; REFER to Section 205-03 . TEST the system for normal operation.
Bedrck47
Full Access Members
Front Axle Will Not Engage
Switches.
Linkage.
Wiring (DTC 1844 or 1845).
Vacuum system.
Shift motor.
Front Axle Will Not Disengage
Switches.
Linkage.
Wiring (DTC 1844 or 1845).
Vacuum system.
Shift motor.
Switches.
Linkage.
Wiring (DTC 1844 or 1845).
Vacuum system.
Shift motor.
Front Axle Will Not Disengage
Switches.
Linkage.
Wiring (DTC 1844 or 1845).
Vacuum system.
Shift motor.
