AnthonyN

Hello,

I've been having a problem with the rear diff in my hurricane xtr. I've had to rebuild it several times in the last month.

Right after rebuild the diff feels good. Nice and smooth. When installed the wheels turn in the opposite direction as they should. However, after a tank or two, the diff feels rough and jerky. The wheels no longer turn in opposite directions. It's basically junk. I've had to finish two mains with the diff this way.

Just yesterday, I lost power to the rear wheels, during a race. I thought my clutch went. But when I checked the rear wheels, they were free. Almost no connection to the internal diff gears.

I'm not a noob. I've rebuilt diffs on other cars for years. I'm confused as to what the problem can be.

When I remove the guts, the spider and flat gears show signifcant wear. Why? The only shimming that can be done inside the diffs is the shims behind the 4 spider gears.

Does anyone have experience with this issue. Any ideas.

nitrosportsandrunner

when rebuilding, what did you use for grease?

is there any chance you didnt tighten the diff case good?

you "shouldnt" have to shim the spider(planitary) gears.

what condition are the bearings in?

ehroof

Could also be a sloppy diff housing, i have had this happen to my rs4, after 3 rebuilds in 5 tanks of fuel I just replaced the diff housing and its been good ever since.

nitrosportsandrunner

didnt think of that one, but it makes sense. the housing could be the cause of play that is wearing out the gears.

AnthonyN

I used 3000wt in the rear.

I'm sure the case is tightened. I paid special attention to that because to me that's the root of the problem. Let me explain. If I stack the gears in the case, there appears to be about 1mm gap to the top of the case (where the flat gear would be if it was attached to the crown gear).

All three diffs have a small washer behind the spider gears. So I just reused them. Its funny that those shims do not appear on any exploded view.

I ordered a diff case and some new gears. I'll replace evything when it comes in. I hope that's it.

What is really weird is, there was nothing wrong with the diff. It ws working fine. I just opened it to clean the original grease and replace it with 3000wt silicone oil. It hasn't worked right since.