I'm prety sure the problem is the carriers... I had to replace the front diff yestersay and when I took it apart, the diff housing was in pieces... replaced that with the only spare I had... Now get to order more parts including the ffs027.. The diff housing broke because the carrier arm snapped, letting the gears collide and smash though the plastic housing... Never had this problem until I put in the os 18... anyway, love the engine and its a small price to pay for the speed and fun...