Tom Rathjen

Greetings.

I have a 1988 944 automatic with about 150K on it. And it has developed an increasingly annoying rattle when idling, which is originating from the torque tube area. I have researched as many posts on this for an automatic as I could find, and I think that it is probably the torque tube bearings gone bad. But before I dive into this, I thought I would share the exact symptoms to see if folks out there concur with my diagnosis.

- Rattling occurs when idling, not when driving/moving or at engine rpm above about 1K
- Rattling does not occur on initial startup when cold, but begins only after it has warmed up about 15 minutes
- From under the car, it sounds like the rattling noise is coming from both the front and back ends of the torque tube.
- Looking through the hole where one would normally inspect a clutch on a manual car, I can see the flexdisc/damper. And it looks fine. Definitely in one piece. (Well....I can see there is a hairline crack. So, if I end up replacing the torque tube, I should probably replace this also. If I can afford it or find a good used one. But I think this is a pending failure, and not contributing to the current rattle noise problem.)
- Looking through the various openings on the bell housing in the rear between the transmission and the torque tube, it appears that all is normal. The clamp that attaches the driveshaft to the torque converter assembly is tight, and the plate that the torque converter attaches to is in one piece with all bolts tight

So, based on all this I'm thinking it is the torque tube. Looks like I can get a rebuilt one for around $500, which isn't too bad. But I honestly don't know if I can tackle this as a DIY job. From what I have read here and elsewhere, it requires removing the transmission (very heavy) and also dropping the rear suspension. Yuck.

Thanks for your feedback!

hardtail15

Unfortunately you probably aren't going to really know until you start taking things off. The torque tube can make things resonate a lot, for example when my rubber center clutch went out I thought it was something in the trans axle because the sound was resonating through. Typical sound for torque tube bearings going bad is that it sounds like there's a bunch of marbles rolling around in there, is that the sound?

and taking it all apart is definitely a job for two especially if you've never done it before, good luck!

968 GUY

I just did my 968 Tiptronic damper plate. There is a bushing in the front and a clip. Clip could have come loose or the bushing could be worn.
You may want to check the torque converter also, I now have a noise at the transaxle that I need to investigate.
It may be hard to find another automatic torque tube.

Tom Rathjen

I'd have to say that it doesn's really sound like marbles to me. More like a steady banging.

968 GUY

Loud banging? I would check the damper plate more closely, there are lugs on the plate which provides away to make it home or to the shop when the damper fails.

jeffrsmith

My '87 Auto also was rattling when I took it apart, although the damper disk was not totally separated in the middle, it was cracked most of the way around. I am in the process of putting the car back together now with a static clutch setup - hopefully it will fix my rattle. I expect to have the engine back in the car in a few weeks, only time will tell.

Tom Rathjen

Posting a follow-up. I finally started tearing into this right before Thanksgiving, and it took several sessions of work up until this weekend. Yup, problem was definitely the damper disk. Rubber was completely separated around the circumference. I don't know how I couldn't see that through the clutch inspection hole, but I guess it was because the separation was so far to the outer edge. Anyway.....bad part out, and now planning to put in a fixed clutch setup. Parts on order. (Not looking forward to putting the transmission back in.)

TexasRider

I have a little rattle at 2300 rpm or so. It is really only there then it goes away. Not before and not after that rpm. While it sounds like a loose exhaust somewhere in the left rear, it is not. Everything there is tight. I cant duplicate the the noise on the rack.

Reaching for straws I have thought it could be some baffle loose and rattling in the catalytic converter.

The more I read on these torque tube rattles, the more I am starting to suspect something here even though my clutch seems to be fine.

I am glad you found yours - kind of anyway.