Section 718 (Automatic Transmission - 4L80-E/4L85-E - Service, Diagnosis & Troubleshooting): Noise

WARNING: This page is about a different car, the 2006 GMC Sierra and 2006 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Noise

Checks	Cause
Torque Converter (1)	Loose lug bolts Out of balance Internal failure
Transmission/Engine	Misaligned
Case Extension (19)	Output shaft support bushing is worn.
Reaction and Output Gear Sets	Flats on gear teeth or teeth improperly machined
Oil Pan	Dented