Rear end....

Bottom line first

What are the chances the diff is blown?

Is there any kind of stop leak for differentals

What is the proper torque for the pinion nut/yoke if I have to replace the seal?

The story....

So I FINIALLY got the LT1/T56 installed, what a job...throttle, breaks, everything working, so I take it out for a test run. Figuring if something is going to go wrong, it will if I punch it a little. So still in 1st I punch it to about 3/4 pedal.....what a sound! It gets up to about 2500RPM then a loud bang, followed by nothing....I think mybe the clutch took a dump so I try and shift into 2nd, no prob! Start to let off the clutch and I hear banging.......must be U-Joints. So I pull it off into the neighbors driveway (Yeah, I didn't get very far!) and look under it....my poor driveshaft is sitting on the ground I put it up on the torque arm and push it back to my driveway, I don't hear any odd noises as I push it... Jack it up, and find that a U-Joint strap is loose....1 bolt....I already had some "odd trouble" when I had noticed after the car was shipped the fuel feed line was cut in the rubber section....so anyways, I go and see about new straps....can't find any that fit (Motormite sucks...totally wrong, didn't come close to fitting) so I decide to move on and replace the sway bar bushings....Then it happens, I notice the blue-green Redline oil very and I mean VERY slowly dripping down the yoke. I try and test the posi, turns out the "wheels in the air" case won't let you test the Zexel Torsen rear, so now I am faced with possibly a blown rear, and I guess definatly a blown pinion seal. I can't see how the rear went, I did the buildup of the 10 bolt (28 spline axles, Ratec pinion spacer, diff support cover, etc). I am trying to be able to drive this thing 100 miles tomorrow, so I'd rather not pull the cover to check the rear if I can avoid it.

3/4 pedal would be what 3500 rpms? I could see a 3k+ clutch dumb wreaking havoc on a 10 bolt. Id say pull the cover and check its not ThAt big of a job and will give you a definite answer.

Lol not a clutch dump, let me rephrase: I let off the clutch slowly until I was totally off, and barely on the pedal (Man that clutch is smooth), then I got on it, I stopped at about 3/4 pedal b/c I didn't really want to break the tires loose. It got up to about 2500 or 3500 rpm, just before I went to shift, and then bang :) A few other facts I missed saying. The driveshaft did hit the yoke, it looks like only once, one strap for the u-joints has a small gash in it, and the other has a small chip out.
Oh, could my seal just have been knocked loose? hmmmm....I might have to pull the yoke and see if I can't jam the seal back in....
I don't want to pull the cover because I have nice redline oil in it, and I can't get more tomorrow (when I have a long trip to make)

Maybe the weight of the wheels makes it hard to turn it? I would use a breaker bar or something to turn the yoke or better yet, have someone turn the wheels and see if the yoke moves.

the yoke moves. The wheels spin. I was more concerned with the leak. I just told the whole story so it didn't sound like I went under my car one day for no reason and just saw it leaking, it was after the u joints went and the driveshaft smacked alot of stuff...

Pinion oil seal....

With the original question I would assume just the seal. Can't you catch the fluid and pour it back in???

Doug, a ten bolt should take a 3500 clutch drop. My buddies "98 TA with heads and cam ran 3 consecutive 12.34x's while dropping the clutch at 4900, so he dropped it at 5200 and cut a 12.23x. That was on a prepped track and on slicks, with a rearend having around 80,000 miles on it. Then again I blew one up behind my '90 IROC with a 305??? They are tempermental, like all things, one is going to take insane abuse and last and the other will blow under mild abuse. On the upnote I put a 3.73 posi axle together and put it in my IROC last night as a replacement for the 3.08 and worn posi that I blew up.

Martin

How about catching the fluid and then replacing the cover with a better one that has some sort of support on it for the end caps. Those also have drain plugs for this sort of thing.

Sorry I didn't reply, I haven't had internet access. On the advise of some trusted individuals, I drove it around town a little bit, and came back. Leak was gone. Just vanished as mysteriously as it showed up. Their guess, pinion seal was dry for having sat for so long (Sorry a little more back story, the car blew the trans a year ago next month, I got the new t-56 and lt1 around march/april. In may while waiting for some bs part I pulled the cover to check alignment pattern to make sure nothing had loosened up in there before the trans died. It sat in searing texas heat with no oil until mid august. Then after the first short drive a little oil leaked). So they think it just moistened back up and expanded like it should. I drove 100+ miles to Harrisburg, PA from Hatfield, PA no issues, except for a terrible vibration which I think may be the driveshaft. (which I will see about getting re-balanced this weekend when I drive back)
So thats the end of that :)

awesome man glad it worked out all good. Couple questions for ya. What year t-56 is it? What gears are you running in the rear? And most importantly how do you like the new tranny. I'm going to try to save up this winter while shes tucked away so i can afford to do the swap

Doug it's about the best swap you can do. :D

i would assume as much. Once on this board (forget who) someone said "driving an auto is just one step above riding the bus". I know that autos are great for drag racing but i dont care id rather enjoy my car. just wondering more as to what tranny gears hes running as well as rear end gears and how thats working out for him.