Mark R.

Okay. I thought I'd better start a new thread for this.

I crawled back under and snapped a picture to show what I was trying to describe in the other thread, regarding my 87 S4 daily driver.

And as I said, I can't believe I just noticed this, and furthermore, I REALLY can't believe I've been raging around for all these years with only a portion of the front spline engaged in the coupler.

It wasn't until I recently looked closer at all the other posted pictures that I realized mine has an inordinate amount of the splines showing.

When I probe the front coupler splits with a wire, I can feel the tip of the shaft inside the coupler. It reaches about to the end of the split slots in the coupler.

I dropped the exhaust and felt around up inside the rear coupler access hole (the rear bolt was already properly torqued), but I can't really feel any portion of the splines at the front of the coupler.

The car has been like this as long as I've owned it (~8 years) with no apparent "symptoms" (i.e. - I discovered this "visually"). I had performed Earl's Loctite 790 procedure on it years ago (including the telltale paint), and I check it yearly for any movement, but I guess I just never took note of how much spline is showing until now.

One other thing I noticed, it does NOT have the tapered shaft (as I would expect). It appears to have a straight 25mm shaft. Also the front torque tube bearing is exactly 9 inches back from the front of the tube.
--> Is it possible that this is a manual tube that somehow got installed in my car..?

Thanks very much in advance for any comments, suggestions, or guidance,

Mark in Atlanta (Long Time Lurker...)

87 S4 Grandprixweiss Auto w/LSD (Daily Driver Since 2004).
88 S4 Silbermetallic 5 speed w/LSD (Weekends - Currently Apart).
84 S Schwarz Auto w/LSD (Sold in 2007 - Daily Driver 1997-2004).

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Dean_Fuller

Mine was EXACTLY like yours...until I fixed it. Mine has the same 25mm rod as well. In my case the vibration dampner was loose inside and I think acts as a slide hammer to move the rod rearward.

Notice the splines on mine before.

Black Sea RD

Both picture and video show a 25mm drive shaft that was incorrectly positioned in the TT and rear transmission coupler.

Instead of placing the bolt through the drive shaft rear groove designed to allow the rear pinch bolt to pass through, the bolt was forced by the stepped down portion of the drive shaft ahead of the rear groove.

Picture shows the transmission end of a 25mm on top and a 28mm drive shaft. The rear bolt is sometimes forced just ahead of the last bit of splined portion ahead of the groove toward the engine which would be to the right of this picture.

The vibration dampener coming apart does not have any affect on the drive shaft moving within the couplers.

Black Sea RD

Mark,

You have a correct auto torque tube in your car.

The front bearing being back about 9" from the engine end is good and also about normal.

The drive shaft however is not correctly placed and not enough spline is captured in the front flex plate clamp.

HTH,

Mark R.

Hi Constantine,

Thanks very much for the reply. That does help a lot.

So I guess the big question is should I loosen everything and attempt to work the shaft forward into the proper position, OR just continue to live with it as it currently is (and has been for years now)..?

And, where exactly does all that excess shaft length go in the rear? Is there really enough open space behind the rear coupler without it making contact with anything, or disrupting something back there..?

And lastly, is the necked down diameter on the shaft as deep as the depth of the cutout where the bolt is supposed to go? I'm wondering if the current rear bolt location may be placing an additional side load flex on the shaft...

Thanks again,

Mark in Atlanta.

87 S4 Grandprixweiss Auto w/LSD (Daily Driver Since 2004).
88 S4 Silbermetallic 5 speed w/LSD (Weekends - Currently Apart).
84 S Schwarz Auto w/LSD (Sold in 2007 - Daily Driver 1997-2004).
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Black Sea RD

Hi Mark,

To fix it is up to you. Obviously it has been working just fine for a long time.

Sometimes when you attempt to fix something like this you might make it worse and it becomes a full blown TT R&R.

depami

Makes sense that you could create a problem trying to move it.

Normal thrust bearing concerns still apply though, correct?

Cosmo Kramer

How many miles on the car?

Black Sea RD

Yes!

According to Mark he used loctite on the splines and the white mark seems to show no movement. Samll straight edge against the flex plate to confirm would be a good thing.

Mark R.

Yes. That is correct. Migration has not been a problem. I'm just concerned about the smaller than desireable amount of spline engagement.

I heard back from DanielD on the other (his) thread. He had the exact same situation on his S4. It turns out he was able to loosen his and work the shaft forward, back into the proper location, and it has been fine since.

So I'm going to loosen everything on mine and try to leverage it forward. I mainly just want it to be correct. I will report back with the final outcome.

Thanks guys,

Mark in Atlanta.

87 S4 Grandprixweiss Auto w/LSD (Daily Driver Since 2004).
88 S4 Silbermetallic 5 speed w/LSD (Weekends - Currently Apart).
84 S Schwarz Auto w/LSD (Sold in 2007 - Daily Driver 1997-2004).
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fraggle

When I put my transaxle in, I was able to move the shaft with a small pry bar into the proper position from the back and front.

Bilal928S4

You will have to get the loctite to release before you can move the shaft.

Tails

The loctite will probably require heat to move the clamp. I would suggest you google loctite with the number or grade and read the removal procedure.

A butane torch will probably be suitable, however, I would have a fire extinguisher available, all tools to hand, slacken off both clamps and ensure you have safely procedures in place. Clean up any oil or other flammable material and also include a safety person.

Tails 1990 928S4 Auto.

Mark R.

Well, the Loctite 290 definitely did require some heat to get the coupler to break loose and move (as their website suggested). It was a bit scary using the torch under there, but I was careful, and it seemed to work out okay. Here is a picture of the completed task.

The situation was exactly as Constantine had surmised. The rear clamp bolt had been tightened into the necked down portion of the shaft, and NOT in the proper groove where it belongs.

I seem to remember Capt. Earl warning that it would be difficult to remove the coupler after using the Loctite 290, and MAN was he right. I have not reapplied the 290 yet, but I may go ahead and use it again, now that the shaft is correctly located.

For now, I have just left everything torqued tight, but I will need to pursue something a bit more permanent. Luckily, this car has one of Louie's original x-pipes on it, so access to that area is pretty easy.

--> A question for those of you currently utilizing the P-Klamp:
Does it still require you to periodically loosen and relieve the movement, or does that clamp successfully resist (eliminate) the creep of the splines..?

Thanks, Mark in Atlanta.

87 S4 Grandprixweiss Auto w/LSD (Daily Driver Since 2004).
88 S4 Silbermetallic 5 speed w/LSD (Weekends - Currently Apart).
84 S Schwarz Auto w/LSD (Sold in 2007 - Daily Driver 1997-2004).

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Mrmerlin

Have you ever rechecked this front and rear clamps?
How many miles after this was discovered was it checked?