hi guys, i bought a second hand hyper 7 about 2 months ago and havnt had any problems until now. it appears the teeth on the rear diff have been shredded, anyone had the same problem/suggestions to prevent it ? also is there anyway to only buy new teeth rather than a whole new diff ?

Hi I put a link in the other thread for diff gears.
As its second hand I don't think you can complain too much. You do not know how much the previous owner used them or whether he shimmed them after rebuilds etc.
Diffs should last quite a while but are still 'wear and repair' items. They are part of the transmission and should be checked and rebuilt with new gears/ componenants where necessary, as well as having the fluids changed, regularly.
Shim them correctly though and they should last a long time.

how do u shim gears correctly ? what diff oil/silicon would u sugest ?

I run 5000 : 7000 : 3000 in mine but its open to experimentation.
Most companies manufactuer diff oils and theres no gain in taking one over another.
As for diff shimming try [link=http://www.rc411.com/pages/howto.php?howto=35&page=1]this[/link]. Its easier than explaining on here