1041 diff exploded!

[shellshock]

I'm curious on this one. 1993 945 Turbo with 130k miles. Long story short, we got the walbro installed and the main pump bypassed and went out to do some smokies in a nearby parking lot. We do a couple of burnouts and such when suddenly the rear end locks up. I managed to get it unlocked by flooring it in reverse. The car made it home fine minus a terrible racket. Still does burnouts though!


Also, the diff currently acts as if the locker is engaged. Taking slow sharp turns results in the inside tire scrubbing. There is also a hole blown into the cover.

I've had plenty of RWD Volvos, and many that made more HP than this car (13c at 13psi, IPD cam, cam gear, OBX exhaust, and a few other things) and never had this happen. Even on the old 300k 240. I know anything can happen not knowing the previous history of the car, but it just seems odd that it goes this soon trying to spin a stock set of Hydras.

Our next approach is to install a 1993+ NA rear end due to the 4.11 gears.

[Jeh]

I killed a G80 a few months ago. It wouldnt unlock at all.

[ryanfay]

Have you seen the inside of a g80 before? Those little baby pawls are supposed to catch and engage, locking the diff for max durifto. Only problem is the spiders are already spinning and have already picked up plenty of momentum. If youre on a surface with plenty of traction, your ass is grass. Remember these things are designed for added traction when needed while behaving like an open diff normally.
Also fyi the 4.10 pinion is weaker than the taller ones.

[745 TurboGreasel]

Bit of debris is lodged in the spider gears, or behind a ramping plate.

Why do you think the Chevy guys call it a 'gov-bomb'?
It's not made with beef, yet every engagement is harsh as can be, because wheelspin is required to initiate lockup. Inherently unsuitable for any type of high performance driving.

[towerymt]

The old Volvo guys I talked to say the G80 case spreads and spits out the governor weight, usually poking a hole in the diff cover. I don't know if that's why, but the parts are tiny and the loads at high wheel speed must be high. $500matt spit pieces through the cover doing a ~100mph wheel-speed burnout. At least I think it was a g80 at the time...the vid is around somewhere, and quite hilarious.

We lucked out on our lemons car and it didn't puncture the diff cover whenever the G80 broke (during a race I think). Ours went to 1WD, no other signs...til I popped the cover and metal bits came out. Pinion was chipped on one tooth, otherwise it looked pretty good!

That rear survived 2 more races, about 35hr track time, til the ring & pinion failed 7hr into our last 14.5hr race. The second G80 we put in was fine, though. I'm blaming the prior damage and the lack of proper setup on the 2nd G80. Lash felt OK, but it didn't have much bearing preload, so maybe lash was off a bit too.