[Biturbos4] S4 transmission tunnel shuddering, ding-ding noise

[Steve Munk]

Thanks everyone for your responses. I'll consolidate my replies in  
this one post. Status report at the bottom of this message.

On Nov 7, 2006, at 1:31 PM11/7/06, Single Malt wrote:
> Try temporily defeating the ESP to get going a bit
> quicker (and more fun) in slick conditions.

Steve, I did that in a snowy parking lot. Very fun!

> Is it possible that the sound was coming from the rear
> diff?  Maybe even transmitting through the drive
> shaft?

All things are possible, though that wouldn't explain the car  
shuddering. *Something* relatively heavy and off-balance was making  
the car shudder. The driveshaft seems to be the only thing in that  
region of the car that could do that. I think you got the sound  
transmitting through the driveshaft portion right though (see below).

On Nov 7, 2006, at 2:29 PM11/7/06, Brandon Rogers wrote:
> Sounds like a tough one- but also check the halfshafts.  Who knows..?

Brandon, the halfshafts appear to be good.

> Several of us take our cars on icetracks and flog them - snow that  
> flies
> off the spinning tires does tend to build in the exhaust/driveshaft  
> area
> - it melts at first then re-freezes as it builds.  It does cause some
> interesting and frightening noises.  Might also want to let the car  
> sit
> in a warm garage and see what melts - then drive again see if the  
> noise
> is still there...

I might not have made it clear but putting it in a warm garage was  
the first thing I did. I took a drive a couple days later after  
putting the heat shielding back and reassembling the exhaust and  
nothing had improved.

On Nov 7, 2006, at 4:58 PM11/7/06, allroader wrote:
> Run your issue by the S4 Forum at AudiWorld, to see if anyone else has
> experienced this.

Neil, I tried that but disappointingly there were no responses in 24  
hours. Now my post is buried under a bunch of newer posts.

Here's the status report. Last night I removed the driveshaft. After  
shaking it, I found there is nothing loose inside the rear section of  
the driveshaft to make the 'ding' sound as I had guessed. The CV  
joint at the front end of the the shaft is nice and tight. The CV  
joint at the rear is relatively loose and clicks, so it's probably  
bad and needs to be replaced. Assuming that's the only problem, my  
theory is that the CV joint was binding up, then violently releasing  
(causing the 'ding' sound to echo down the hollow shaft), then  
binding up again etc, which caused the shaft to wiggle off balance,  
which caused the shuddering.

I took the driveshaft to a local driveline shop this morning. He said  
he couldn't repair it and couldn't get a replacement end joint or  
even a replacement driveshaft. No surprise there.

I found a site online that supposedly sells a refurbished S4  
driveshaft for $400 plus $60 core charge plus shipping:
http://www.autopartsauthority.com/apa_driveshaft/audi~s4~2001~parts.html
I called them up. Of course they don't actually have them in stock  
nor do they know when they will, but I should check back next week!

Then I lucked out. I stumbled upon Blaufergnugen (blauparts.com), and  
though their website doesn't spell it out, I called them and found  
out they stock individual replacement parts for the S4 driveshaft:
http://www.blauparts.com/parts%20dept/driveline/ 
Audi_Quattro_Drive_Shaft/ 
Audi_Quattro_Drive_Shaft_Propeller_Shaft_Kits.shtml
So for less than $200 including 2-day shipping, they're sending me a  
replacement end joint for the driveshaft which I'll have the  
driveline shop install. Should be here on friday. I'll let you all  
know how it goes after the driveshaft has the new end joint installed  
and whether that actually solves the problem.

Thanks again,
Steve
--
Steve Munk
HPC Systems Analyst                  '01 S4 biturbo, silver 6-speed
Arctic Region Supercomputing Center  '01 A6 2.7t, gold 6-speed
University of Alaska Fairbanks       mailto:fxstm at uaf.edu