Fun with the drive shaft

[scot_w]

Back in November I posted to "The great drivetrain mount debate..." thread that: I had a clunking sound under acceleration. NGP checked it out and found the drive shaft was moving around due to a worn mount. Audi wanted $1700 for a new driveshaft w/support, 034 has a DRIVESHAFT SUPPORT CENTER BEARING that will be put in as soon as it arrives. $100 plus labor = better longevity, performance, deal than $1700 + labor.

This is one of those things that might have been better off left alone.

In addition to replacing the engine mounts and getting some oil leaks fixed, I decided to get a clunking looked at. NGP got the car completely apart and decided that the problem was partially the bearing, but worse the universal joint appeared to have failed and it needed to be replaced. They put the car back together and ordered a used driveshaft for just under $500. Two weeks later I took it back and had the new to me (used) part installed. It was pretty late when I picked up the car and I guess they did not have much of a chance to test drive the car because as soon as I got up over 40 MPH the car felt like it was going to shake itself apart.

I limped around over the weekend, called NGP, and had a discussion that revolved around taking the drive shaft to have it balanced or getting another one. NGP opted to get another one so I have been limping around getting my fillings shaken loose. I am trusting their telling me that nothing bad will come of the shaking, but man will I be glad when they get my baby fixed.

[jcjohnson33]

I had that problem but it only shook during acceleration from a stop then went away once the drive shaft centered itself. I also ordered the center bearing but the center bolt that holds the two pieces together broke and I could not separate the shaft to replace the bearing. Plus the way the u-joint is installed there is no easy way to replace it as they are on my truck. I ended up ordering a remanufactured one from Colorado driveshaft for 310 + 100 core deposit. It came with new cv joints and boots at both ends and new center bearing and new u-joint and was balanced. Even the cv joints were pre greased, since installing I have had no problems. It shipped to me free and came with a pre printed label to ship my old one back for free.


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[a4kamila6]

I wouldnt drive like that at all. when something isnt working the way it was designed to or when its beginning to fail, other parts usually wear faster also and in turn fail. Hope everything will be okay


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[rollerton]

If it's clunking around I don't think it's the U-joint. First thing I'd try is swapping some new/ better CV's onto it. That center joint is really durable- and usually it's a CV that worn so that as it spins it transfers the 'wobble' down the shaft to the U-joint and actually makes it look like the center hanger has failed or the U-joint is seizing. If that makes sense. It's because the only part of the driveshaft system that has any flexibility to it is the center hanger- so at some part of the spin the CV bearing hits a worn spot and won't allow the shaft to turn at that angle, so the center hanger absorbs the driveshaft deflection and it looks like a wobble.

From what I've seen the driveshaft CV's all seem to be the same in Quattro / 4-motion cars from 99 to 2005 auto OR manual.
Find a good pair of CV's to swap onto the driveshaft, it's pretty damn easy job- dropping the driveshaft is about a 20 minute job once car is off the ground. Hard to do it in the car with the exhaust in the way..but possible.

[scot_w]

New to me driveshaft did the trick. No more shake rattle and roll.

On a side note I did the APR ECU upgrade and while I am not sure how much more power it makes (it is a 4.2 after all), it was well worth the money for the smoother throttle response. Kicking myself for not doing it before.

[A6Rick]

Good info on this thread. Been a while since I've been on the zine. But I have a question to the op. You say you get a clunking sound. I get a rumbling, deep rattling sound under acceleration. And good away once I hit 20mph. Center bearing us the culprit? Or something else. I have a 4.2 btw

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[Scotty@Advanced]

New shafts can be had for under $650.

http://advancedautomotion.com/shop/p...roducts_id/331

[scot_w]

Good info on this thread. Been a while since I've been on the zine. But I have a question to the op. You say you get a clunking sound. I get a rumbling, deep rattling sound under acceleration. And good away once I hit 20mph. Center bearing us the culprit? Or something else. I have a 4.2 btw

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The clunk was the driveshaft literally hitting things. The rumbling was similar to what I got once the driveshaft started spinning. The center bearing from 034 is an upgrade from the factory bearing, if it would have solved the noises it was a much less expensive option than the driveshaft, and even with the new to me driveshaft we used the 034 bearing.

[scot_w]

New shafts can be had for under $650.

http://advancedautomotion.com/shop/p...roducts_id/331

Oh, NOW you let me know you have them.