The expert suspects a locked torque converter. As a temporary test, locate the purple wire at the brake-light switch above and behind the brake pedal, cut it, and tape the end so the converter cannot lock. If it remains locked, shift from Drive to Reverse at slightly raised engine speed to release it. The car may be driven short distances, but the converter should be replaced and the purple wire reconnected afterward.
The owner of a 1988 Oldsmobile Delta 88 Royal with 205,645 miles reported that it first struggled to move after a complete stop and then would not move in any gear. The owner asked whether the automatic transmission was at fault and noted that the engine was not original. The expert suspected a locked torque converter, suggested disconnecting the purple brake-switch wire as a temporary test, and recommended replacing the converter and reconnecting the wire.
