Originally Posted by Nemesis
IF that is the case (sounds like a likely situation t osome of us) the it may have to do wit the new support beam that GM designed for the tranny. The pics of the support beam came out a few weeks back with little to no explanation. Right now, dubbing this as the cause of the delay is still speculation.
I think the support beam isn't designed for the tranny (there are no problems), but to get a higher stiffness in the drivetrain.
Particularly the diff will get a steady position even with the higher torque of the GXP/RL. This could reduce the problem with the whining or solve it totally.