So, I have had my 94 968 cab since March...been really enjoying it. Fixed a few things, car is in great condition at 49k miles.

I was in the drive through a couple of weeks ago and the echo off the building revealed a slight rattle. I had the car up on my ramps yesterday to tighten the belt running my alternator (which I replaced a couple of weeks ago). While I was under there I slid back to find the rattle I had heard earlier. Well, it seemed to be coming from the oil pan...then I slid back a bit more toward the rear of the car and it sounded like it was coming from where the torque tube (?) meets the tranny. I am still a total noob at this, so hopefully I am not mistaken with my identification of parts.

So from what I have read, it seems like this could be the torque tube itself, or bearings that are in there (I guess where it meets the transmission)? Of course, I might not know what the hell I am talking about. That's where you guys come in...any thoughts?

Thanks in advance!

 

Highly unlikely the t-tube bearings by the trans at the back are worn, the ones at the front of the tube always go first and certainly not at 50k miles.

Rattles at the back are normally from the steel plate above the rear muffler being loose. The rattle travels through the floor pan and sometimes seems like it is coming from the t-tube. I would look at that plate and the other plate above the catalytic converter before digging any deeper.

 

I will definitely check that out. I wouldn't be surprised if you were right, as I have not experienced any problems during my drives...and the sounds doesn't seem to change with the position of the clutch. I'll check it out ASAP and let you know.

Thanks MAGK!

 

are you sure what you are hearing is not the gears in the trans rattling against each other in neutral? if someone presses on the clutch and puts the car in gear and the sound goes away, you at least know it's somewhere in the drive train and not the engine. an automotive type stethoscope can help

 

In our experience rebuilding torque tubes, most 944 and 968 torque tubes usually have the rear most bearing fail first and is the noisiest of the four.

Rattling could be the rear coupler coming loose that joins the drive shaft to the transmission. You can pop off the rubber plate of the aluminum flange of the torque tube that is bolted to the transmission and have a look and make sure all the bolts of the coupler are tight.

You should also check to see if the front drive shaft coupler is tight too. The 968 has a two part drive shaft at the front allowing for the drive shaft to be unbolted and the clutch shaft be pushed back onto the rest of the drive shaft to remove the clutch without having to remove the whole torque tube as in all 924s and 944s. If the front bolt is loose, it will also rattle. You can get at it by looking for the access hole at the front of the torque tube.

Another thing to check is to see of you have a split torque tube in your 968. MY 1994 should have been changed to a solid torque tube but you never know. The split torque tubes have a bad habit of allowing the front bearing to walk around which then can come apart, allowing the drive shaft to vibrate more. The split runs from the front about a third way down it's length and can be seen from the bottom after removing the heat shields. The split is usually covered over with silver metal tape.

If you do have a split torque tube, we would investigate this a bit further by shining a flashlight up into the split and verifying the health of the front bearing unit. Our website shows what can happen when the front bearing walks and becomes damaged.

HTH,

 

The rattle occurs when the car is in neutral, as well as when it is in gear with the clutch engaged. You cannot hear it when the car is in gear and moving, or when it is in neutral and the rpms are taken above an idle.

If MAGK's hunch is incorrect, I will take off the heat shield and inspect the torque tube to see what's going on in there.

 

Okay, I finally got back under the car yesterday. The rattle did not seem as bad...in fact, there didn't seem to be a rattle, but rather just a noise coming the housing around the front end of the torque tube. Can anyone tell me what's going on in there when the car is running, but stationary and in neutral? Is anything moving at that point? Could I be hearing the pump in the oil pan?