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View Full Version : Neighbors, can you explain how this happened?


Brett
09-09-2002, 07:11 PM
http://www.zianet.com/brettj/rich3.jpg
Saleen91
09-09-2002, 07:22 PM
:eek:
HoustonLX
09-09-2002, 07:35 PM
:eek: That will leave a mark! Looks like a good reason to upgrade to me.
Rusman
09-09-2002, 07:50 PM
Ouch!!!

:eek:
white87306
09-09-2002, 08:58 PM
Is that what happens whn you don't ground the hanger for the differential relay?

Please tell me that's the old one before the 3.90 install
Neighbors
09-09-2002, 09:45 PM
Hmmm, let me regain my composure then formulate a hypothesis (read: lie!).

It appears to me that Rich did not deburr the 31-spline t-lok or stress relieve it properly. The desired effect is from 3.2' off of the concrete, directly onto the concrete. Any deviation in height or surface will drastically change the outcome, as seen here...

I think what may have happened here is that Rich was doing a burn-out in a high horsepower car, and caught traction with one side only (on the dry side). The sudden shock loading to the cast iron diff, coupled with the stress concentrations on an undeburred/non-stress-relieved unit caused the failure...

Since you replaced the differential relay, it is very unlikely that yours will suffer the same fate; unless you got a faulty relay to begin with (the QC is pretty tight, so I doubt the possibility)...

One other cause may be something getting loose, like a pinion gear fracturing, and lodging between the ring and pinion...

Two details here: the 31-spline unit has square shoulders and a 7/8" diameter pin. If you swapped these into your car, I'm afraid the warranty is voided...

Thanks for the heart check!

Nay!
Brett
09-09-2002, 11:01 PM
Yep. 31 spline T-Lock 8.8 behind 500+hp.

Surely you didn't think your handy work would come apart like that? Besides, it only has maybe 1 mile on it.:fu:
Neighbors
09-10-2002, 06:24 AM
LOL! Well, just for a nanosecond...

If you have enough poop to do that, then I need to step up a bit for the blow-up competition to be held at RCR. I think I'll add a 300 shot; yea, that's it...

Did he ever figure out what really happened? The pin hole is not wallowed out, so I doubt the pin came loose. The fractures on both sides appear to be identical, so I don't think it was an inclusion or flaw in the casting. It would be real interesting to see what the other 'leg' og the t-lok looks like. It looks like the tranverse loading (caused by the contact angle of the gears) just 'popped the top' on the ole diff, as the ring side is the side that is fractured off. Hmm, odd...

I still contend he hit a dry spot with the right hand side while doing a burn-out...

Please don't try this at home kids!

Nice picture Brett! Got any more?

Nay!

BTW, I've had nightmares of this sort of thing happening, LOL!
Brett
09-10-2002, 09:51 AM
http://www.zianet.com/brettj/rich4.jpg

http://www.zianet.com/brettj/rich.jpg

http://www.zianet.com/brettj/rich5.jpg

The rear came out of the above mentioned 500+ hp 1st gen Lighting.
Neighbors
09-10-2002, 10:15 AM
Wow! That's impressive! No damage to the pinion gears; there goes that thoery, LOL!

It lloks like one side of the carrier failed in a brittle failure (the side with a bit of a peak to it), while the other side exhibits a bit more ductility.

Hmm, I wonder if the head of the pinion gear didn't snap/shear off? Any pictures of that? Based on the marks on the diff, that may have happened...

No Regis, that is not my final answer... :D