johnu

I am trying to chase down a rattle underneath my 87 auto.
What are the signs of a bad tube? What does it sound like? Does it make noise in all gears including park?
Thanks
john

FredR

There are three common problems in that area viz the torque converter bearings [2 No], the bearings in the torque tube and the noise attenuation damper that can work loose. The damper is often characterised by the thing rattling around and sliding back and forth under acceleration and brake. The torque tube bearings can migrate and cause issues as the rubber mounts age and harden and torque converter bearings are probably the most likely issue.

If these things have not been attended to in the history of the car then there is a good chance one or all of them will be marginal or shot.

When torque converter bearings are failing at some point you will hear them squealing. That you detect a rattle would make me more suspicious that the damper is coming loose.

Needless to say when dealing with one of these items it is probably prudent to deal with all three given the lengths one has to go to to get at them.

Bertrand Daoust

To answer your last question, the drive shaft turns when in park.

So I'd say that you could hear something with a bad bearing/damper when in park.

Does the sound change with the RPM?

davek9

On an Auto the Drive Shaft is directly connected to the Flywheel, if the engine is running the shaft is spinning inside the TT and so is the Torque Converter.

The hollowness of the Tube tends to echo sound everywhere, if the car is an '87 and the bearings have never been replaced it's time

You should consider the Black Sea R&D Super Bearings, and not put old hard rubber back in w/ new bearings.
Replace the Torque Converter bearings while you are at it as they could be the source of the noise too and this is the time to do so.

Dave K

Adk46

I've got the signs myself, rattling, confirmed by Stan. He said I could keep driving it for awhile. It's job 1 this winter.

johnu

Just looked at Dwaynes write up...wow...i am not looking forward to this job!

OTR18WHEELER

Some say failing TT bearings simulate a growling sound, ...like a panther.

Catorce

Replacing the bearings is an evil job. The easiest thing to do is to call up Mark Anderson and get a replacement - he rebuilds these.

And then you know it's done right!

928 at last

As long as things (the old bearings and balancer) stay aligned in the tube on removal, it's actually not that bad. If they go slightly cockeyed....then a different problem. Our old dearly departed friend Greg used to use a 3/4 ton pickup on a hoist as a press when this happened....
Nonetheless...it worked.
I, on the other hand spent hours with a torch and brute force to get the bastiches out.
Putting the new stuff in is a breeze.

928 at last

Oh, and by the way, I would agree that the Black Sea solutions are the way to go. When I did mine it was super bearings and clamp on reassembly. Silk since.

928 at last

Not sure if your model year has the tapered drive shaft, but if it does, while you're in there you may want to deal with that issue too and be done with it.

chart928s4

+1 on the tapered driveshaft replacement, Super Bearings and torque converter bearings. Eventually it will be needed and it's a lot better on your schedule vs. at a random time. But it's a big job and even bigger with all the WYAITs.

Could it be something simple though? A rattle doesn't seem like a bad TT bearing. Loose heat shield, exhaust hanger etc?

928NOOBIE

+ 1 on Black Sea R&D Super Bearings....go to the website and compare the 2 pieces of hardware and it isn't even a question. Yanking the tt isn't fun...I put these in and also noticed reduction in vibration...mine also was shot and needed servicing.

Constantine used to provide a service where he'd ship you a tube with the bearings installed...you put in your driveshaft and install....I went this route and was nice to have the peace of mind ....maybe check and see if thats still an option. There will be significant freight costs as you can imagine; and you send your old TT to him either as the rebuildable core or for exchange after the fact....

Adk46

Indeed. On my car, the noise sounds very much like some loose sheet metal somewhere, coming from everywhere, a bit muffled, but loudest when putting an ear behind a front wheel. A random rattling frequency, not tied to RPM. For a long while, I thought something had come loose inside a catalytic converter. But when I probed with a stethoscope, I found that the noise was loudest at an opening to the bell housing, suggesting it was coming from the forward opening of the torque tube.

At Frenzy last year, Stan put his ear behind a front wheel and said "Yup, torque tube. Get the Constantine replacement TT." He also said it was not an emergency - I hope he's right, since I didn't get to it last winter and plan to drive it to Frenzy this month.

The noise appeared on the first drive of 2016 after the winter layup, and has not changed since.

Sound familiar, John? I'll let you go first....

johnu

This sounds like what I am experiencing.
This is the car that just keeps on giving.....me a headache!