mikehayes

Hey guys, I think I got royally f*&^%$#. I bought a rebuilt torque tube off a guy on CL for 80 bucks, no miles on it. Seemed like a trustworthy guy, had had many 944's and the leftover parts to prove it. So while I was installing new torsion bars, I threw the new tube in. It's a late model tube whereas my car is an early car. They should swap fine. They didn't. I now have literally everything back together and I go to put the couple on between the shafts, and they're not lined up. Now I know what you're going to say "oh the tt shaft isn't in or out far enough to get the coupler bolt in." Nope. I mean the shafts don't share the same center. The tt shaft is a few mm's higher than the trans. "No big deal" I think, I'll just loosen the bolts that hold the tt and the transmission together, and I'll pry it on there. I pry with a long *** bar, I feel it move maybe 10 mm's. Good, I got it on. Nope. I pushed the tt shaft forward almost a centimeter. Sooo, my questions are: 1. Did I just move my pilot bearing back a centimeter? Is that even possible? Does the hole the pilot bearing sits in allow the bearing to move forward? The gap between the transmission shafts and the tt shaft is clearly larger than it's supposed to be. And 2. What the hell could possibly cause this misalignment? The rebuilt torque tube spins beautifully. I can't see how the shaft could possibly be out of center in the tube, but somehow they don't line up. Thanks.

PS. If I have to drop the rear suspension, clutch bellhousing, trans, exhaust, etc. again just to fix this, there will be an opportunity for you guys to find hundreds of new porsche parts if you're willing to sift through the ashes of my garage and this car.

mikehayes

Update, I found this picture

http://s12.photobucket.com/user/leextac/media/Porsche/Picture11-1.jpg.html

Essentially, it shows a lip at the back of where the pilot bearing installs, so it couldn't have slid back. So how is this possible?

Van

Rebuilding a torque tube is a very imprecise science. So the drive shaft will absolutely have to shift one way or the other. Don't worry, it won't pull the pilot bearing out.

Here's a video that I made, showing a little bit:



Driveshaft coupler is around 52:00

V2Rocket

Maybe shaft is bent? Spin it over, is it misaligned the other direction now?

odonnell

If they aren't centered I would bet it's because the Dowell pins are wrong. Sometimes they stick into the trans and sometimes they stick into the torque tube. You probably either have no dowel pins installed, or you have 2 trying to share the same hole. You pull them out with vice grips.

mikehayes

Hey guys, I managed to get the sleeve on both shafts and torque it, but I had to have all the TT>trans bolts out and the TT supported with the jack. The trans was just hanging by the two mounting points. I then got the TT>trans bolts in, but as expected, the holes were all misaligned by the same amount as the shaft was. I managed to get the bolts in using wiggling and force. I would guess that now my rearward-most TT bearing is being pushed down by the pressure from tightening the bolts and may fail early. Oh well. The shaft spins freely so there's only one way to find out....

mikehayes

O'Donnell: i knew about those from the last seven times I dropped my transmission, and when I took all the bolts out they were what was failing to let the two shafts align properly. I removed them both and left them out. It was the only way to get everything together.

V2: I checked it when I bought it and when I noticed the problem. It spins perfectly round.

Tiger03447

Glad to see that you got the trans back in,Mike. Interesting dilemma, though. Perhaps Dimi or Constatine can comment..

mikehayes

Thanks, I'm still not sure of the root cause so it would be nice to know why it happened as I can't find any way to explain it. If I remember I'll give an update once I get the car back on the ground.

Otto Mechanic

Mike, there's just one thing that bugs me about your story; you got a rebuilt torque tube for $80?

Sorry. That's just a bridge too far. No one gets a rebuilt 944 torque tube for $80.

mikehayes

Believe me man, no one was as shocked as I was. I asked him the price and I damn near lost my mind. I was just shopping for some wheels and this guy mentioned he had a torque tube so I asked if by chance it was rebuilt because I knew my bearings were bad. I wasn't even planning to do anything about it because I knew how time consuming and costly it was to do it. And on top of that I found it literally the day before I was going to drop my rear suspension? It was too good to be true. But I got there and checked it out, and I can say beyond a doubt that at least the outer two bearings are brand new with custom machined delrin carriers and bushings. And the inner ones are too quiet not to be new also. The guy referenced an old dimensions sketch of the carriers that I've seen on this forum before. He did them on his lathe himself. He didn't have any more cars to put it in just parts. I didn't question it.

Otto Mechanic

It's just one of those things that always happens to someone else...

mikehayes

Yeah I figured that out. The front to back movement of the shaft wasn't my main concern. It was the up and down misalignment (which I know is not a typical issue) that still has me wondering.

Otto Mechanic

I had that problem as well, another member on this list told me to check to make sure the two alignment pins at the top of the TT bell or the transmission (they can be in either part) were there. It turns out one of them was missing and that made it impossible for me to line up the drive shaft with the transmission input shaft in the up/down dimension.

I took it apart again, installed the pins correctly, then put a trans. jack under the rear of the tranny to get everything lined up. Kevin Gross did the remote diagnostic and even mailed me a replacement pin!

mikehayes

Otto, read a few posts up, this has been covered. (tldr, I had to remove both of mine).