2004 Jetta TDI new clutch. How have a problem

2004 Jetta TDI new clutch. Now have a problem...

New clutch was installed in January. Ran it easy to get through the "break in" period. I gave it like 1500 miles to settle in. Clutch is smooth in normal driving. When I step on it I get a vibration that shakes the whole car. As soon as I let off the pedal it smooths out again.
I would think if there was a problem with the clutch assembly I would see it all the time. But, I do not. Only when I step on it, not even floor it. It does not appear to slip as the tach seems to be indicating correctly.
First thought was a motor mount. I took it back to the shop that did the work and he went over the car today. He checked the CV joints, suspension, and a few other things I could not see from the distance I was at. He is suggesting a new driver's side motor mount, as I was thinking it was.
What does the Encyclopedia of TDIClub.com think?

Make sure your CV axles are still tight to the transmission output stubs. They can be a pain to get tight and stay tight. Not the best design.

Second that, make sure all 6 bolts on each axle flange are still fully seated and tight.

Many have had those axles come apart after a clutch job or axle replacement because they weren’t properly torqued back in place.

How were the inner CV joints checked? That is probably the most common thing to cause this problem...pitted inner hubs on the inner CV joints. This may not be revealed without removing and taking the joint apart.



It may not be the only cause but it is perhaps the most common.


Another is the use of cheap Chinese solid shaft RH axles. Was this replaced at some time?
The axle will resonate through the cabin at around 1800 and 3600 engine RPM. Sound familiar?

Here are some "dumb" questions- Did you replace the flywheel when you did the clutch? Where was the part sourced? What clutch was it? Is the car tuned or otherwise modded to increase power?

DuraBioPwr said:

Make sure your CV axles are still tight to the transmission output stubs. They can be a pain to get tight and stay tight. Not the best design.

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When he did the inspection yesterday it was brief. He has a good reputation working on VW / Audi. He checked the CV joints, inner and outer. Saw him do that much anyway. I will ask for this to be double-checked before any other work is done. Thanks!

Tdijarhead said:

Second that, make sure all 6 bolts on each axle flange are still fully seated and tight.

Many have had those axles come apart after a clutch job or axle replacement because they weren’t properly torqued back in place.

Click to expand...

I'll be sure to ask. Thanks!

BobnOH said:

Here are some "dumb" questions- Did you replace the flywheel when you did the clutch? Where was the part sourced? What clutch was it? Is the car tuned or otherwise modded to increase power?

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It is a LUK 17-050 clutch pack, pre-assembled with a new SMF. The car has a Malone 1.5 tune, but I got the tune for economy, not power. I also changed the 5th gear out to a taller gear (0.658), again for economy.

I like JETaah's post: a photo tells the best story.

But what an inner CV joint with that type trouble usually does is cause steering wheel shimmy when you press the go-pedal. It doesn't shake the whole car.

Just for future reference though, when funds are not copiously available, you can swap the inner CV joints side to side, clean and re-lube, and motor on. The boots are unique, but the CV joints themselves are identical.

I would figure that what the mechanic did was check the CV joints, inside and outside, for play both axial and concentric. In this case with these symptoms, that probably is adequate with the caution that when the source of major vibration is remedied, then smaller vibrations like the shimmy described above might then be unmasked.

This type problem can be devilishly difficult to diagnose. Good luck and keep after it.

Cheers,

PH

I don't get a steering wheel shimmy. It's the whole car. Really thought something was going to break. Let off the pedal almost instantly and all was fine. Tried it a second time on another occasion and it did the same thing. So, I called the shop that did the work to have him take a look. The shop owner is honest as can be. Really a nice change over dealing with ANY VW dealer or repair shop. I wanted to get an idea of what the gang here might think. Really appreciate the information. At the very least I can make a few more suggestions if the motor mount change doesn't address the problem.