i have a 07 m8 that has about 3500 miles on it and the diamond drive performed great. Let me younger brother take the sled out and it somehow lost the oil in the diamond drive and it wouldn't shift in to reverse, still went forward fine. Took it out and opened it up and the brass shims had failed. Everything else looks to be in great shape except those brass shims. Can you buy those anywhere or do I need to purchase the whole planetary gear set?