Just purchased M600, service manual has not arived. Reverse drive quit working on left side. Took off side cover and clutch disk between the 2 metal plates was missing. Found paper thin sections of disk inside. Purchased 2 new clutch plates. 1. The clutch plate for the forward travel looks to be about the same thickness as the new ones, but I want to replace it also so they are both the same. 2. Should I replace the other 2 clutch plates on the right side also? 3. How tight do you tighten the clutch adjustment nuts? Thanks for any information.