Technical Service Bulletin PIP4379M — 2008 GMC TOPKICK

This Preliminary Information communication provides information to the technician about vehicles that have not engagement into drive, delayed, no engagement into reverse, and or a range inhibit. Technician may find Diagnostic Trouble Codes P0701, P0731, P0732, P0733, P0734, P0736, P0751, P0756, P0761, P0776, P0843, P0848, P0873, P0877, P0894 or P2723. Technician should follow published Service Information diagnostics for Diagnostic Trouble Code P0701 first. Technician will also ensure the fluid level is at the top of the hot band when the transmission fluid temperature is 175° Fahrenheit. Diagnostic Trouble Codes P0701, P0731, P0732, P0733, P0734, P0736, P0751, P0756, P0761, P0776, P0843, P0848, P0873, P0877, P0894 or P2723 can set by the following fluid service/filter change, transmission service involving removing the pan, low fluid level caused by leaks, or after long periods of storage. If the fluid level has been properly checked using the HOT check procedure listed in Service Information document 2408059 and any of the Diagnostic Trouble Codes reset during a cold start inspect the internal suction filter for possible cracks. If no other concerns are found inspect for a stuck lube regulator valve in the pump cover due to debris.