GM Service Manual Online
For 1990-2009 cars only

Checks

Cause

A whine which may be RPM or load sensitive, or ceases when the TCC engages

Torque Converter (1)

Verify that the noise is internal to the torque converter by placing your left foot on the brake with the gear selector in drive. Then momentarily stall the engine. The torque converter noise increases under load.

Final Drive

Inspect the final drive gears