I am putting together an rc10l4o and after assembling the diffs have found a gritty feel. odd thing though is that I got 8 diff balls, and a kimbrough diff that has 12 outside holes and 6 inside holes. The diff is dead clean and greased perfect, can I have gotten the wrong size diff balls? maybe the wrong wrong diff? If anyone knows anything about this please let me know.

the diff balls go in the outside holes of the spur gear, if you only have 8 you need 12 for the kimbrough gear your using. Dont use the inside holes.

try that ............. hope this helps

yep, thanks