Bill Ball

Yes. I certainly would expect Greg to service those bearings. It's a relatively easy job. If you decide to do it, the torque tube has to come out, of course, but the tranny does not (just loosened and slid back). However, with an S4 do NOT attempt to remove the torque converter itself with the tranny still in the car. It's not possible, although it is with S3 and earlier model 928s. You can remove the cover, being careful that the TC does not try to come out with the cover. If the TC does get partially out, it can tear the seal on reinsertion. Learned that one the hard way.

I've actually never seen or heard bad TC cover bearings. When I replaced mine at about 230K miles, trying to address a vibration and a noise in that area that sounded like a bearing whine, the original bearings were like new and replacing them changed nothing. Others have observed vibrations and whining that were due to these bearings wearing out. The rattle you have MIGHT be them, but I would expect them to whine or growl, so I hope it's the bolts mentioned. Also, the flex plate can partially fracture. I have seen that, but the loud rattle noise it created was only on start-up and shut down.

Pagnobito

I don't think it's the bearings, when mine were bad the sound resonated all the way up the torque tube and was more of a dry bearing sound more than a whining noise.

Bill Ball

We agree. Just offering it up as a possibility.

jeff spahn

So here's an update. I took the plug out of the bellhousing and checked the bolts. They are all torqued to spec. I can't see any cracks in the flex plate from under there.
I checked the half shaft bolts. They are all tight.

Going to take the exhaust down next, pull the head shields and see if I can check the rear pinch bolt. Then I can inspect the bearing location at the back of the torque tube.

Leon Speed

No need to take take the exhaust down, loosen the rubber mount on the right mid muffler to get the play needed.

jeff spahn

So I used a stethoscope under the car to isolate where the sound is coming from. It is either the TT bearings or the convertor bearings.

I am getting a new drive shaft installed in a torque tube by Constantine with his Super Bearings and sending him mine as a core. Sean Ratts is putting new carrier bearings in a bell housing and flex plate for the install.

With the new bearings installed in the part and a TT to just swap it should be a pretty good job.

With the upcoming supercharger install it would be silly to not fix this issue and break something.

I love this community!

Chalkboss

Jeff, keep us posted. Although it was hard to tell from the audio, I have a similar intermittent rattling coming from the TC on my 87 at idle. New TC bearings, rebuilt TT, etc by Greg a few years ago. I have also checked torque on everything and all to spec.

Some suggest it is the rivets that hold the flex plate to TC, which apparently can come loose and are fixed by replacing bolts with rivets. Don't know about your MY but on my 87 it is a possibility, although a rare problem. I don't know what else to check... the sound is slowly getting more frequent.

ROG100

Don,
I have seen the rivets on the early cars doing exactly this - rattle. They appear to be solid in the flex plate but in reality are not. Drilling them out and replacing with bolts fixes the rattle. IIRC there is a Porsche bulletin on the subject.
Roger

SeanR

Thought this was only on the '87's. ??

jeff spahn

This is describing me. Getting more frequent. We will have to check the rivets and replace when have the RR out. [BOLD]SEAN. please note this to do list.[/BOLD]

jeff spahn

Roger. Can you get the necessary parts to Sean to do this for my car? Be a shame to have it all apart and not do this.

OTR18WHEELER

the ticking sound seems to be rythmic with the idle, its a rubbing tick, not to be confused with the sound Divot makes rubbing ticks.

jeff spahn

During my supercharger install I was able to literally "put my finger on my noise". While the car was on the lift waiting for Victor to arrive, i decided to pull the rear heat shields again and inspect the rear tt clamp again The rear tt bearing has exploded and the outside bearing cage or race or something, not sure of term, has wandered down the driveshaft and rests against the rear TT clamp. I can feel it with my finger in the hole rattling around loose nOh well only a month til the rebuilt TT goes in.

jeff spahn

As part of elimination of the mystery sound I have begun to remove the bits and pieces to get to the torque tube. Underside of my car isn't as shiny clean as Rob Edwards's cars. Makes me feel inadequate in some way. I'll probably go through a bunch of degreaser while I am doing this job and try to clean things up a bit so it is eat off it clean like the SoCal guys cars.

Everything is coming off like the bolts are buttered. Thanks Greg Brown (and the other SoCal guys who helped Ron Perry maintain this car) for keeping everything in such good condition during your work on it.







here you can see the constantine clamp loosened and how it looks when loose on the driveshaft.





left one bolt on the TT so the driveshaft isn't supporting the weight of the assembly before I put a jack under it.



took the plugs out to make the engine easier to rotate. don't have to remove any tubing or anything with the supercharger installed. very easy access to the plugs.

jeff spahn

The new TT is in. Mystery noise is solved.

Part 1 was the rear vibration dampener exploding and sending bits of itself down the driveshaft to rattle on the rear clamp.



Part 2 was the TC cover bearings starting to go bad. They had some in and out movement.

Now that the parts are replaced, everything is smooth smooth smooth.