Whine Type Noise Coming From Rear of Vehicle (Diagnose and Replace Rear Propeller Shaft)

Some customers may comment on a slight whine noise coming from the rear of the vehicle at certain speeds, typically between 72-96 km/h (45-60 mph).

Rear axle "Inherent" ring and pinion gear whine.

All gear driven units, such as automotive rear axles, produce some level of noise that cannot be eliminated with conventional adjustments and repairs. "Inherent" axle noise can be described as a slight noise heard only at a certain speed (typically between 72-96 km/h (45-60 mph) on most General Motors® trucks). The presence of this noise is not indicative of a functional concern with the axle assembly. However, some customers may find that this "inherent" axle noise is unacceptable.

Replace the rear propeller shaft with an aluminum service shaft (utilities) or with a tuned torsional damper shaft (pickups) ONLY after a road test and diagnosis concludes that it is an "inherent" rear axle noise and no physical damage or incorrect adjustment exists.

Important: If the noise is not correctly diagnosed as "inherent" and having a peak in the narrow speed range of 72-96 km/h (45-60 mph), the addition of a tuned torsional damper propeller shaft can aggravate the perceptible noise level. It is extremely important to first diagnose the rear axle noise as "inherent" before installing a new tuned torsional damper propeller shaft.

Diagnostic Information and Procedures Available in SI for Rear Axle Noise

Note: The Cadillac Escalade already has a released propeller shaft damper for production. It has a different u-joint size than the 2WD Chevrolet Tahoe and GMC Yukon, so the service propeller shaft in this bulletin would not work on these vehicles. The Escalade has a swaged steel tube shaft with a damper on the end.

For vehicles repaired under warranty, use: