tpi 421 vette

I pulled the halfshafts, driveshaft, and pulled the broken piece of housing that contains the pinion. It now has a nice big inspection hole!! I can now take the pinion out the front just like a Ford 9".I really expected to see blown up spider gears. To my amazement, the carrier was fine, and the ring and pinion still have all their teeth. It looks like the cause was the case itself failed. I guess the torque on it was the cause of the failure, not a broken piece of something getting caught between the ring and pinion.

Caboboy

This is some pretty interesting stuff Jim. Would it have done any good to cryo the batwing and pumpkin you think........just to move the weak link further out?
I suppose the problem with that is unless you've got CF 1/2 shafts, they'll beat you to death floppin' around

bogus

that's wild! Glad you found the real cause... however, there are a lot of racers now worried!!!

tpi 421 vette

The case was cryoed. Actually everything was cryoed except the batwing. But the batwing didn't get damaged.

CFI-EFI

One of the natural forces in any diff, is for the pinion to be thrust forward. I've seen other rear ends spit the pinion out the front of the diff, but most of those just took out the pinion cage, which we don't have. I don't know that I'd be afraid to replace it, but I know you have bigger plans. Good luck with the project. There's only 6 1/2 months until the track opens.

RACE ON!!!

CORKVETTE1

this is one of the reasons i am giving up racing the vette full time
i just picked up her replacemant this past monday nite

0ski_dwn_it

We manufacture aluminum cam caps for most of the GM OHC engines and one thing is for sure in all the testing we do. Aluminum has very little "shock" resistance. This is not to be confused with yield strength, which is high for alumimum. ie, being able to return to its original position without cracking/deformation.

Aluminum when subjected to "shock" or impact forces, usually fails immediately.

Now relate this to your drivetrain. I hate to say it, but that is why so many guys with manuals kill these rears. That is not to say that damage with a auto is not possible, hell I just twisted my 1/2 shaft into a piece of lycuric. But I think mine was more due to continual fatigue stresses, rather than abrupt fracture, like your differential showed.

If your going to keep running the manual and slamming everything with zero "load" or the lash removed, then you will continue to have failures. These failures can be greatly reduced/avoided if you can "load" the drivetrain to take out the lash, when you dump the clutch. That is why I think that our rears are lasting much longer than most peoples here, with 3x the amount of runs on them.

I am nearly sure if I ran a trans brake with my setup, it wouldn't last past 1 dead hook. To expect it to would be absurd.

At any rate, glad to see you did not trash the gears as well.

1996man

what is the batwing?

Ramrod92

Dan, it's the rear cover on the Dana 44 or 36. They are different though.

65Z01

Is the batwing & rear cover the only difference between D36 & D44 or there other important reinforcements in the D44?

bogus

The D44 has a larger case and can hold bigger gears... also, the carrier is stouter.

They look the same, kinda, and fit the same, kinda, but thats about it.

It's like the difference between a 265 ci SBC and an LT1, sure, they are both SBC's, but nothing is interchangeable.

thetoy

Thats exactly what i did to mine this summer it didn't brake anything inside either. I just tore the diff in two.

comp

pinion walking up the ring gear..... can you make a support???

tpi 421 vette

Ski dwn it... your exactly right. It was the shock that killed it. I made it off the line in one piece but when I hit second, that is when it broke. I think a Ford 9" with 35 spline axles and a spool should solve my problems. Also the ring and pinion are in one piece, but unfortunatley when the pinion exited the front, it left some nasty looking marks in both of them. I would be afraid to reuse them. But the Unitrax carrier came thru like a champ!

jburnett

Jim's entire rear was cryoed... I know, I did it... I'm still quite surprised at the damage; I can't count how many passes I have on my D44 with a stick with NO failures. But, everything has it's limits and I believe there are differences in the housings just like there are differences in everything else manufactured in mass quantity. This is the first failure we've had of a rear end component in three years; it pisses me off... But, it's bound to happen.

Jim, you need to call me regarding your solid axle setup. The way you're thinking about doing it is going to cause problems with the instant center (like I had mentioned). I actually have some pretty definitive information on it now from my chassis builder.
-Jeb

tpi 421 vette

Jeb, I have changed my plans about the 4 link set up. I am now going to do something similar to Hooked up's car. That way I can run longer 4 link bars and get the instant center correct.

comp

??????

tpi 421 vette

I was originally going to install a 4 link like Hoover did without cutting the rear floor, but have decided to do it like Hooked up which involves cutting the rear floor.