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For 1990-2009 cars only

Range Inhibit And/Or Will Not Move - keywords drive inoperative reverse

Subject:Range Inhibit and/or Will Not Move

Models:2001-2005 Chevrolet Silverado Classic
2006-2007 Chevrolet Silverado, Silverado Classic
2001-2005 GMC Sierra Classic
2006-2007 GMC Sierra, 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This PI was superseded to update model years.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 PIP3497.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

No Forward or reverse. Main pressure is correct with a turbine speed reading of "0" RPM on the Tech II scan tool. Transmission line pressure will be normal.

Recommendation/Instructions:

Inspect for metal debris in torque converter clutch valve (eSI Doc I.D. 1261489 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.

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.