Whitesands

The vibration I can feel is when I’m cruising in D, I can feel it more when accelerating and it almost disappears when coasting, if I change down to 3rd it seems worse, there’s no noise from anywhere, what should I be looking at?
MM's are fairly new.
Thanks.

Mrmerlin

follow this link it should give you pictures of a diagnosis tool to inspect the bearings in the TT

Thanks Dave

http://members.rennlist.com/sharkski...DriveTrain.htm

http://members.rennlist.com/sharkskin/

Mrmerlin

I would suggest that one or more of the drive shaft bearings has moved or the damper in the TT has moved OR the trans mounts are weak

SharkSkin

I think what Stan means(thanks for the plug) is that you can use wire probes to see if the bearings in the TT are out of position -- they should be about a foot from either end of the torque tube, give or take. There are pictures of tools that I made to check for fore-aft movements in the bearings over time here, but you can just use any piece of stiff wire to get a general idea where the bearings are without turning any wrenches -- just use the inspection plugs at either end of the TT. What can happen if a bearing moves is, the bearing can end up moving to a point where the central shaft is a smaller diameter than where the bearing is supposed to ride, and this allows the shaft to flex and cause vibration.

chrly924s

Both my bearings had moved AND the damper had come out of its carrier and was sliding back and forth. I had all kinds of vibrations.

Giovanni

Go with Constantine's bearings and loose the dampener.

Dan87951

I would also check the back center axle nut. I believe this should be torqued to over 300lbs but double check. I had mine go loose on me and was having vibration issues as well. I tighten this center axle nut and all was well but it ended up ruining the wheel bearing and hub so when I did my torque tube I bought good used ones and replaced than.

Whitesands

Thanks all,
will try all what you say and report back later in the week.

Black Sea RD

Thanks for the plug Gio! Glad you like your rebuilt TT by Greg (Blown87) using our Super Bearings.

Been asked about this feature quite a bit. We've designed our steel Super bearings so that three of them make up the weight of the Porsche dampener that comes apart with age and can move the bearings from their position as another poster on this thread mentioned.

Ivan, from what you've described and as others have said, it sounds like your torque tube bearings are not supporting the drive shaft as they should. Good luck with your diagnosis and let us know what you find out!

Cheers,

James Bailey

He could also have a single bad injector or plug/plug wire. The cars will run pretty well on 7 cylinders but the miss is much more pronounced under load....goes away on decelleration coasting...

Black Sea RD

I always start with the simplest diagnosis or failure mode and then work to more complex problem possibilities.

Already steered a 928er with a weird vibration in his drive line away from his TT as being the problem. Turned out to be his torque converter.

Whitesands

I finally got round to checking to see if the bearings in the torque tube have moved, I dropped the lower bell housing and had a look inside, I was greeted by one of the bearings looking at me, well maybe one and a half inches from the end of the tube and I guess this is the cause of my vibration.
So that’s my next job, ho-hum

Dan87951

Boy your gonna have fun changing that out!! LOL actually it isn't all that bad, just take your time and label all the baggies. I did a lot of while you were in theres and my car been awesome so far. Actually haven' put a dime into it in the last 12k miles since other than oil and gas. It's nice to be reliable again. Definitely do the transmission lines and torque converter bearing!!

Black Sea RD

This is a very common occurrence as the TT internals age. The hard rubber on the bearing housings becomes even harder and shrinks a bit so they start moving around in the TT due to the drive line vibrations.

Will not be surprised if the bearing inserts have also shrunk letting the drive shaft spin within them polishing a nice (well, not so nice really) groove into the drive shaft.

Good luck with the TT R&R!

Whitesands

Thanks Constantine and everyone else for your replys,
I need to read up on how others have removed the tt and go from there, the present tube (Rebuilt) was fitted in 1999 at 187k and has 101k on it.