I realize that the 10 bolt is not a very strong rear-end, and I will buy a 12 bolt when I can afford one, but I broke my posi at the strip the other night and am wondering why the posi broke vs. the ring or pinion.

My rear end is as follows:
GM 7.5" 10 bolt
Moser forged axles (c-clip)
Yukon 3.73 gears
Auburn Pro posi
T/A cover w/ bearing cap studs

I was running street tires (no traction whatsoever) and was slipping the clutch from idle off the line as there was nothing but tiresmoke otherwise.

The car was on its fifth run and I was about 30 feet out when something in the rear went out. I pulled off the track and took off the cover to find a pile of gear teeth on the bottom of the diff case; Only they were not from the ring or pinion, but the horizontal spider gears in the diff.

This confuses me as I would expect the ring gear to break and not the diff. I have about 7500 miles on the diff which is 99.999% street driven. It is about 2 years old. Is this a known problem with this brand of diff or a fluke?

 

That's pretty weird, I thought the auburn pro is the strong version. I broke my stock Auburn posi, spider gears exploded - before the ring/pinion. But that's the stock one.
I'd be looking closely at how it failed, and seeing if I could blame Auburn for it, maybe get a new one, or a discount on a new one.

 

if you go town this thread page, you'll read were I broke the housing on my Auburn after a burnout