PhillBrown

It started suddenly 3 weeks ago-
Its a heavy vibration that comes thru the shifter,steering wheel and pretty much all over the place.
It is there at idle and thru gears 1-4 and to a lesser degree 5th and 6th.
Disengage the tranny
( downhill) and it is hard to notice.
No CEL
No codes via vag-com.
No misfires at all.
Just heavy vibration

I thought vacuum and found that one of the Drive Units arms had broken.
I repaired it to little or no effect. The rest of the vacuum lines looked good and after spraying Propane around each and every connection I believe them to be sound.

Inspected mounts and found snub-nose very decayed and replaced it yesterday and it has helped somewhat but vibration still making it unfun to drive.
The other mounts looked good- no leaks, but I think I'll replace them in any case next weekend.

I think the most frustrating thing here is thinking I found the solution only to be thwarted by what may be many issues. The car is very nice and it came to me as a gift and so Im not fuming nor mad - just stumped.

Does anyone see something I may have missed in this search.

Thanks
Phill

lyleswk

It's probably something in the drivetrain. Have you grabbed the halfshafts and tried to wiggle? There should be little to no movement.

PhillBrown

Yes that makes sense.
I will check that out. Service manual first. Under Audi second.
and thanks lyleswk

John535is

Check for loose wheel nuts. Sounds stupid but I had a car turn up with the wheel nuts loose. I had forgotten that one till I was watching one of those highway patrol shows on TV recently and a car in New Zealand lost the wheels on a highway after a service when the mechanic clearly forgot to tighten them. Lucky for the driver there was a concrete strip separating from the oncoming traffic. The police officer walked up and undid the remaining nuts by hand.

I would remove each wheel, check for anything failed or loose, check the strut mounts and CV's & half shafts (as per lyleswk), Check the wheel rims, any recent excursions into pot holes or gutters? Are the balancing weights (if any) still tight? check the tires for distortion, flat spots etc then refit each wheel, tighten correctly etc

There are 2 engine mounts, plus the snub you replaced, 2 transmission mounts and the diff mount that you need to check.

PhillBrown

Thx for the concise list John. It will come in handy no doubt.
And Lyleswk I did get under the car today and the shaft were fine- alittle rotational movement and no lateral.

Going back to my original post

"Its a heavy vibration that comes thru the shifter,steering wheel and pretty much all over the place.
It is there at IDLE and thru gears 1-4 and to a lesser degree 5th and 6th."

If you rev the motor at a standstill you get the heavy vibration as well.
The vibrations increase as rpm's go up and decrease as rpm's go down.

I would think it was a misfire on one cylinder because its like clockwork-
rev it up and the drumroll gets faster let off the gas and the drumroll slows down. I'm repeating myself arrgg

No cel no codes no misfires according to VAG-COm

I want to add that the vibration is heavy under load and diminishes when not under load.

But I have to say I think this is an engine related problem. But I'll add that any time I'm certain of something the facts get in the way.

Thanks
Phill

lyleswk

I don't think it is misfires. If the misfire was that serious, you would get a CEL.

When you did the snub, did you follow the procedure of adjusting it closely? I.e. let the engine run and rev a few times and ensure it is still centered in the mount?

PhillBrown

Yes I tightened the Cup a little more then hand tight and let the engine settle down and then tightened it in place. A Few times in fact.

The snub did help the issue of vibration. It reduced the intensity.

I was under the car this morning while idling to inspect the other mounts and the tranny and motor mounts looked intact. I was looking for movement to see if one or more of the mounts was bad.
It was just idling but I just had a buddy sit in and rev it up but its impossible to see were its coming from.

I'm going to order new mounts and install them this weekend with the idea that if the snub-nose helped then replacing the other mounts can't hurt.

Thanks lyleswk

dennisd356

Check your flywheel, flywheel has a rubber section between steels that cracks and causes vibration had same problem on 3 Litre 6 speed.

PhillBrown

I was thinking that this vibration could be centered around the clutch/flywheel because after all new mounts it is still with me. But the good news is that it now starts up between 2000-5000 RPM range in any gear or in the driveway.

So the new mounts have helped.

From all the info I've read concerning audi/ vibration mounts are the first thing to look at and clutch/flywheel come up second and so I will take your suggestion Dennis and look at it tomorrow.

thx