PIP3497B

File in Section:
Service Bulletin
Bulletin No.:
Date:
PIP3497B
February, 2013
PRELIMINARY INFORMATION
Subject:
Range Inhibit And Or Will Not Move
Models:
2007-2013 Chevrolet Silverado
2001-2007 Chevrolet Silverado Classic
2007-2013 GMC Sierra
2001-2007 GMC Sierra Classic
Equipped With a Allison LCT1000 5-Speed or 6-Speed Transmission RPO M74, MW7
This PI was superseded to update model years. Please discard PIP3497A.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
No forward or reverse. Transmission line pressure is found to be correct with a turbine speed reading of more than
200 RPM below engine speed in park or neutral.
In some cases the turbine speed RPM may be at or near "0" on the Tech II scan tool.
Recommendation/Instructions
Inspect for metal debris in torque converter clutch valve (see disassembled view of the oil pump cover in SI item #6).
The torque converter clutch valve will be stuck in the stroked position.
The debris must be removed and all valves and bores in the pump body must be cleaned to insure each of the
valves move freely in their pump cover bores.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.