Automatic Stability Control (asc) problems of the 2003 BMW 3 Series

While driving 2003 325xi on county hiway slowed down to make right turn to about 15-20 mph. Halfway through the turn loud noise emitted from transmission area (previous failure of trans. Comp. Module @ 1500 miles-replaced by dealer) and vehicle locke up, hard enough for myself and my wife to move forward against the seat belts. Pressed on accelarator, motor running but would not respond. Dodge truck struck my vehicle in rear, driver and witnesses saw no brake lights or other indication I was stopped other than not moving forward. Shut car off. Had to restart car to move same to side of road, respnded normally. Towed to dealer, unable to find anything abnormal. BMW to send engineer to shop.