: Sheared a bolt on the rear diff yesterday

08-02-08, 10:59 AM
I dont know if this has happened to anyone else, i searched for it but couldnot find it. I was drivin home from work yesterday, takin it easy. I came around a corner and got into it a little bit after i had straightened up and heard the biggest bang i have ever heard. I knew it wasnt the pinion support because that is more of a thud and this was a metal to metal bang. So after i limped home i crawled under the car to see my rear diff hanging about an inch lower on the passenger side. Through more exploring i noticed that one of the three maing support bolts is gone. From what i can see there are three main bolts that hold the rear diff in place, there is one on the driver side, one on the passenger side, and your pinion support. Well the one on the passenger side has sheared of, it is still in the rear end, but not in the frame. I already called the dealer and am getting it taken care of on monday, but i thought i would just share my pain with you. Anybody else had this happen?

Street Rod Concepts

08-02-08, 11:15 AM
That's a big a$$ bolt. Never heard of it happening.
My guess is, that it got loose. Then diff started moving aroung a bit under torque. After a while, the stress just snapped it.
At least she got you home, and you don't have to be towed to the dealer.

08-02-08, 11:38 AM
Its gonna have to be towed. I work at a street rod shop and replacing the bolt is no problem for me, but i dont know what else it may have tweaked when it came loose so i wanna get everything checked out, and i am gonna make them change all the mouting bolts for the diff.

I just had my pinion support bushing changed somewhere around two months ago, so i am gonna put it all on them.

08-02-08, 11:47 AM
... I just had my pinion support bushing changed somewhere around two months ago, so i am gonna put it all on them.The smoking gun. :stirpot:

08-02-08, 04:33 PM
Am i seriously the only V this has happened to?

08-02-08, 05:16 PM
I haven't read about anyone else having this issue. Do you have any pictures?

08-02-08, 09:40 PM
Make sure you do a close inspection of the front support loop. This illustration shows what happened to mine on the right, and the car was STILL DRIVEABLE. The diff on the left is the one in my car now that has been scratch-built from STEEL, and you can see how much more girth we put on that area. Good luck.

08-02-08, 11:10 PM
I have snapped the bolt that keeps the diff from swaying, this is probably the same one as you, as it is thick and is about 5-6", with a thread at the top, non-thread for about an inch, and the threaded the rest of the way down.
I snapped this twice, the diff can sway once busted, and a tow truck is needed. After the second time, I took the GM bolt, major POS, and took it to a machine shop near the airport, they ordered an aviation-quality bolt and threaded it to spec, and got it to me in three days. Their cost was $50.00 for two bolts (always get a back-up on custom work), which was about $1,000 less than ARP wanted.
Mine busted both times under 3,000 rpm,,,