Originally Posted by teknorc

Every center diff on every vehicle creates heat. Creating heat in the center diff is inevitable. How hot depends on many factors. Track conditions, traction level, driving style, ambient temperature, build method, etc. all affect this.

Suzuki, if you have the older style diff cross-pins (not slotted on the ends) and gears, this could explain some of the higher temps. The new diff cross-pins (TKR5149) and gears (TKR5150) are smoother and don't allow the mesh to change internally. They still heat up, but not as much as the older style parts.

That said, in nitro and long electric runs, 160-170 is totally normal for a diff. 190-200 is on the high side, but if your diff is smooth and you've checked the internals, then you're probably fine. Make sure you are filling the diffs up all the way with all of the gears installed, then wipe off excess fluid and install the spur gear. Running without enough fluid can lead to a hotter diff. Make sure your outdrives are properly greased and smooth. If they are binding or otherwise not allowed to spin freely in the sleeve, this will make the diff heat up. Hope this helps.