Brian C Grand Haven , MI September 05, 2016 Appliance: Whirlpool Microwave Oven 1.5 Cubic Foot MT4155SPS5 Whirlpool Microwave Mt4155sps5: Turntable not turning. How to replace Drive Coupling. The drive coupling broke and after some observation the motor did not seem to be turning either. To repair, the perimeter housing screws need to be removed to gain access to the motor. That is the hardest part. Then just disconnect the wires from the old motor and remove it. Screw in the new motor and put everything back together. The drive coupling presses onto the motor from inside the main compartment. Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes