Q: Loud whining noise - 2008 Chevrolet Trailblazer

Hi there. Depending on when the noise occurs I would be able to diagnose this issue better. If the noise occurs right when the engine is started then most of the time it is caused by a failure in the fan clutch on the engine. It is very common for these clutches to fail and cause this type of noise. It can also be low power steering fluid or the water pump. I usually pull the belt off of the engine and spin each accessory while I listen for the noise. If the noise only occurs when the vehicle is moving, then it may be in the transmission.

When one of the thrust bearings fail this noise will occur. It can also come from the rear differential. I usually get the vehicle in the air at that point and run it to try and isolate the noise. If you want to have this whining noise inspected, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this problem.