GM switched to a flat gasket around the pump housing instead of the tried and true O-ring. This gasket failed causing the pump to lose fluid and pressure which made the trans pump wear itself out and no longer pump fluid. The trans would hold up to about 10 mph at 10% throttle then slip and never shift again until you shut it off and started over. Power train warranty was 75,000. This happened at 77,000. I got no help at all from GM. I even had it inspected before the warranty ended to make sure there were no impending issues by the Cadillac dealer in Orlando, FL.