This is a diagnosis that may need a set of chasis ears installed to narrow down the source.
Transmission sounds reasonable, but a noise can resonate. There is a technical service bulletin about a whine that GM appearently is unsure of....
This was date in 2007. The same tsb was issued in 2005 but said to replace the axle...
You may also be able to replicate the noise on a lift and use a stethescope to narrow it down.
Need to narrow down the source to better continuing troubleshooting.
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Monday, November 16th, 2009 AT 5:00 AM