CAB AR-OPEN ROPS 3265510 - Caterpillar

CONFIDENTIAL TIBU2646-00
TECHNICAL INFORMATION BULLETIN November 6, 2002
Off-Highway Truck 797 (5YW), 797B (JSM)
Component Code(s) 3139SUBJECT: THE 171-1008 LOCKUP CLUTCH VALVE SHOULD BE MONITORED AFTER A TRANSMISSION FAILURE HAS OCCURRED
PROBLEM:
Several lockup clutch failures have occurred because of excessive clutch slippage. The cause of the increased slippage has been determined to be low lockup clutch control pressure. The low lockup clutch pressure has occurred after transmission failures have contaminated the compartment with debris. After a transmission failure or transmission control filter bypass event occurs, the performance of the 171-1008 lockup clutch valve can degrade because of contamination.
SOLUTION:
After a transmission failure or transmission control filter bypass event occurs it is recommended to replace the 171-1008 lockup clutch valve and recalibrate. The lockup clutch slip time should then be monitored weekly to ensure clutch slip time does not become excessive. Use Fleet averages to determine the normal lockup clutch slip times. The lockup clutch slip times for most fleets have been from 1.05 seconds to 1.15 seconds in duration.
If there are any further questions please notify Service Engineer Dave Smith (Phone: 309-494-0923, EMAIL: smithdd).
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