Driving at highway speed, with foot on accelerator, engine stalled lost all power steering and braking capabilities (added motor oil). Violent shuddering and loss of fuel mileage (check engine light) dealer changed motormount, no success. I visited a transmission shop, they tell me it may be the torque converter as they have had to replace them on the Cadillac (known problem). I will ask for old parts if GM needs to review to redesign..

- Salem, NH, USA