Is the B3 piston also called the reverse piston? I had all these problems surface after I reversed the car fairly fast for about 200 feet and then shifted to D. It was fine going back, but the moment I shifted to D and began to move forward the whole car began to shake and vibrate. Could I have damaged the K2 clutch by going fast backwards, and also broken the B3 or B2 piston? I'm not sure what these pistons are and what they do. The invoice I have said the 'reverse piston' was replaced (with a used one). Thanks.