| Subject: | No Movement When the Shift Lever is Moved to D4 or D3 Normal Operation When Moved to D2 D1 or Reverse |
| Models: | 2006-2007 Buick Rainier |
| 2006 Cadillac Escalade, Escalade ESV, Escalade EXT |
| 2006-2008 Chevrolet Avalanche, Colorado, Express, Silverado, Suburban, Tahoe, Trailblazer |
| 2006-2007 Chevrolet Silverado Classic |
| 2006-2008 GMC Canyon, Envoy, Savana, Sierra, Yukon, Yukon Denali, Yukon XL |
| 2006-2007 GMC Sierra Classic |
| Equipped with 4L60E, 4L65E or 4L70E Automatic Transmission (RPO M30, M32, M70) |
This PI was superseded to update model years. Please discard PIP3931G.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may comment that their vehicle has no movement when the shift lever is moved to the D4 or D3 position but there is normal operation when the shift lever is moved to the D2, D1 or Reverse position.
Recommendation/Instructions:
This condition may be caused by a damaged forward sprag assembly (642). When inspecting the sprag it is important to test the sprag for proper operation by holding the outer race (644) with one hand while rotating the input sun gear (640) with the other
hand. The sun gear should rotate only in the counter clockwise direction with the input sun gear facing upward. If the sprag rotates in both directions or will not rotate in either direction the sprag elements should be inspected by removing one of the sprag
assembly retaining rings (643). Refer to SI Unit Repair section for forward clutch sprag disassemble procedures.
If the sprag is found to be damaged make repairs to the transmission as necessary. In the event the transmission has repeat sprag damage the transmission may require replacement to correct the condition. Be sure to contact PQC or your DVM for authorization
if a transmission assembly replacement is necessary.
If clutch debris is found, it is also very important to inspect the Pressure Control (PC) solenoid valve fluid screens. Clean or replace the PC solenoid as necessary. It is also important to flush and flow check the transmission oil cooler using J45096.
Refer to SI "Automatic Transmission Oil Cooler Flushing and Flow Test" for the procedure.
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.
