I have been able to stop the grinding in standard Diff's on my Hellfire after converting to brushless 6s power. My diff were constantly snaping under power/acceleration but not anymore. My trick was "HPI 86598 DIFF SHIM Washer 13x16x0.2mm (10) HELLFIRE" I ended up with 3 maybe 4 of these on the Ring Gear side shimming the Bearing in towards the Pinion Gear but that was enough to stop the snaping under power/accel I also had to 3 maybe 4 to push the Pinion Bearing into the Ring Gear now the Gear mesh in my PLASTIC diff housing is as close as it can be without binding.

Granted if try real hard I could still turn that Pinion Gear over top the Ring Gear if I did not arc the Trottle curve or use the Punch Control feature to smooth out the 6s brute power. But a very cheap get by with impressive results.


HPI 86598 DIFF SHIM Washer 13x16x0.2mm (10) HELLFIRE