pungieEC

Hi

My car is an Audi A4 1.9TDi B6 shape 2003 model with a 6 speed transmission and has 230 000KM on the clock. Recently it started with this shaking and vibrations. When driving at low speed in 2nd gear say about 40KM/h it shakes when accelerating but goes away when taking your foot off the accelerator. When driving at about 140KM/h it vibrates as if the car is falling apart and goes away when removing my foot from the accelerator.

I did replace the whole clutch with dual mass fly wheel 2 months ago and did about 2000KM with it when this shaking / vibration started. I went to some car workshop with a lift and had the car lifted. I checked all the bushes and everything on the suspension but could not find any thing that shows signs of wear.

I did notice that the left drive axle I could pull side to side as if there is play on one of the CV joints. How ever the right drive axle was firm with no play, but noticed a little bit of grease on the inner CV joint boot.

Today I replaced both the inner and outer CV joint on the left drive axle, but the vibration and shaking is still there. I did even notice with the new CV joint in place that there is still play on the drive axle when pulling it side to side.

Should there be play on the drive shaft? Might I have replaced CV joints that wasn't faulty? Should I replace the right side drive axle's CV joints or am I looking in the wrong place for this shaking / vibration?

cmb6s (NoVA)

Honestly, what you're describing just sounds like an alignment or wheel/tire problem to me. Especially when you talk about it becoming worse under hard acceleration. If you haven't had an alignment done, that's the first thing I'd do. Next, I would check all of your tires for abnormal wear and make sure that they are all running the same pressures (around 32 psi). If the alignment doesn't help, get your wheels/tires rebalanced and make sure that none of your wheels are bent. Just out of curiosity, how many miles on the tires?

To answer your other question though, no, I don't believe a CV joint problem would cause the symptoms that you are describing. A failing CV joint may exibit some "clicking" and "popping" around corners, but I don't think you will get a vibration like you were describing.

pungieEC

Hi

Thanks for the reply.

I had my wheels balanced about a month ago and had the wheel alignment done as well. I didn't do much driving since. I drove about 1000KM (620 miles) in the last month. The tires are almost as new. I did about 12 000KM (7450 miles) on the tires. The pressure in the tires is 2.3 bar (33 psi).

I went to different workshops today with every one having some opinion. Maybe read my reply at the other site where I posted.

http://www.audiclubsa.org.za/cgi-bin...m=1278834872/0

What would you suggest?

Many thanks

pungieEC

One thing I failed to mention is that the vibration isn't felt on the steering wheel. When the vibration is there, the gear lever shakes out of control and you feel the vibration pulsing through the seat and floor panels.

cmb6s (NoVA)

I would find it very difficult to believe that the type of vibration you're talking about would be related to the engine mounts. However, you could always get somebody to rev the engine while the car is in neutral and just see how much play the engine has from side to side.

I'm far from an expert in this field, but I would tend to agree that it is likely a clutch/flywheel problem. You can see how my car was acting when the flywheel was ready to come apart <a href="https://www.audiworld.com/forums/showthread.php?t=2785754">here</a>. Also, not having a vibration in the steering wheel would seem to suggest that it is not a wheel/tire/axle problem as I would think those vibrations would travel through the tie rods and into the steering box to the steering wheel.

Stating the gear lever shakes out of control is another clue that the vibration is probably coming from the driveshaft or the gear box, but since you say the shaking goes away when you take your foot off the accelerator, I think it's related to the load on the engine and not the speed of the driveshaft. You also state that when going downhill (where there is no load on the engine), there is no vibration, and when going uphill or on hard acceleration (when there is lots of load on the engine), there is signification vibration. If it was a wheel/tire/axle problem, I think you would see the reverse because going downhill is when the front wheels/axles are loaded the most. When you replaced your clutch, did you install a new DMF or did you have the old one resurfaced?

lyleswk

2 thoughts now that I have read and reread this a couple of times:

1) Don't really think this would cause this, but I assume your snub mount is in good shape.

2) Transmission mount? I have not actually crawled until my car to look where they are, but I understand they are the same part as the engine mounts.

s4master1

check you axles specially the passenger side
if the inner joint has play replace it
very common issue under acceleration
let us know

pungieEC

I have replaced the clutch and pressure plate with new ones as well as the through out bearing. The flywheel is brand new as well as I was told that dual mass can't be machined or which I know of here in South Africa. I replace the slave cylinder as well. It is after some driving this problem started to occur.

When trying to pull away, I feel a vibration / shake. When the car moves, and the clutch is fully out, no vibration or shake. But when the speed goes to 40KM/h it has a slow shaking to it. The faster I go the faster the shake. And when moving to speeds such as 140KM/h it starts feeling like a vibration.

I would say this shake is depended of speed.

I did how ever had the gearbox mounting out and noticed some tears on it. I had the opinion of some other mechanics as well and they said it needs replacing.

On the other hand this shaking/vibration caused the material in my catalyst to come apart which is so expensive to replace.

I thought initially that it would have something to do with one of the CV joints. I noticed that my left side had lateral play on it, but not the right side. I noticed grease coming out on the inner on the right side, but again, I had some opinions that there should be no lateral movement on a drive axle. So I replace both the inner and outer joint on the left side. But after fitting it, I had the same lateral play on the axle. At this point I'm thinking to replace the right side as well, as my opinion is that both shafts should have the same findings on them. Am I right?

I will have the parts by this weekend and will keep you updated.

pungieEC

I got some of the parts today. I only replaced the inner CV joint on the right shaft, and definitely big difference. There is still a faint shake / vibration at low speed, but at high speed from 100KM / h up it is gone!

When i took the boot of from the old, I could see big problems. There was almost no grease inside the joint and the remaining grease inside started to solidify and was clay like. And by twisting and pulling it around I could feel it was kind of stiff, which means it probably started to cease. But when I installed the shaft, still the lateral movement was lacking as on the left shaft, which I assume that the outer needs replacement as well. I hope to get the other joint within this week.

Tomorrow I will replace the gearbox mounting and the front mounting to get rid of that vibration as when I'm getting clutch control.

On the other hand. Does any one know if the lower control bush can be replaced or has it to be replaced with the whole control arm? Seems as if the bush is not of those types you can replace.

De-cat? Sounds like an option, but is there any other purpose the cat has besides keeping emissions low?