Transmission failure

[Racer-X]

Had all the same symptoms you describe only a few more. "strawberry milkshake" (as plano describes) spewing onto the driveway. what happened is the tranny cooler blows into the radiator cros contaminating everything.

This scenario would be easy for you dealer to find though.

Be sure they aren't hiding this condition from you. They may do that because normal GM protocal for this issue is to change the radiator and flush everything. No tranny change unless you get nasty like I did.