Whine Noise In First And Second Gear - keywords acceleration case clash filter fluid oil
| Subject: | Whine Noise in First and Second Gear |
| Models: | 2002-2007 Chevrolet Avalanche |
| 1999-2007 Chevrolet Express, Silverado, and Suburban |
| 1999-2007 GMC Savana, Sierra and Yukon XL |
| with 4L80E (RPO - MT1) or 4L85E (RPO - MN8) |
This PI was superseded to update model years. Please discard PIP3259F.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The 4L80E/4L85E automatic transmission may experience a condition of planetary gear whine noise in first and second gear. The planetary gear noise is typically louder in first gear as compared to second.
Recommendation/Instructions:
This planetary gear whine noise can be characteristic of the 4L80E/4L85E. The vehicle should be compared to an identically built vehicle (same GVWR) for comparison before attempting any repairs.
If it is determined that a vehicle has an abnormal amount of noise and the transmission was built after 9-01-03, perform the Rear Unit End Play Check (SI Document ID # 52027). The correct end play is between 0.127-0.508 mm (0.005-0.020 in).
If end play is out of specification, inspect and replace the output planetary gearset (661 - Output Carrier Assembly and 650 - Sun Gear) as necessary. Set rear end play between .005" - .020" using correct selective thrust washer (674). Target between .010"-.015".
If end play is within specification, transmission replacement is necessary, contact PQC for warranty authorization.
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.
