[s-cars] Audi driveshaft shudder/vibration...

[keithbedard at verizon.net]

Richard,

Thank you for your response.  

My climate control is fixed.  I work with a guy that is an electronics specialist.  He opened the box up, and in under 30 seconds (using an eyepiece loop), he found the problem:  one of two identical low voltage drop regulators was cracked, and one "garden variety" diode was smoked.  He ordered the parts (for a whopping grand total of $1.52) from www.mouser.com, and when those parts arrived, took him under 5 minutes with the solder iron.  Works perfect now, been back in car for two weeks! 

The mounts sound like the culprit, excellent!  Is there a particular way I can confirm that tomorrow morning (I will jack up and get under car)?  I would like to confirm this before I order the parts, and do that repair a week later.  It makes sense what you say - that it could be worn trans mounts making the shuddering, and a worn engine mount allowes the A/C clutch fan some movement, thus creating the mystery squeaking...

As always, many sincere thanks to the other responses, from Vincent F. and Mark T.  I will let the list know the results.

-Keith





>From: rguzz at mindspring.com
>Date: 2007/03/30 Fri PM 03:40:24 CDT
>To: keithbedard at verizon.net
>Subject: Re: Audi driveshaft shudder/vibration...

>Hi Keith,
>A couple of points...earlier with the climate control problem we discussed the inoperable buttons...I spoke with SJM from whom I buy a lot of parts and he suggested running the diagnostics on the climate control before doing anything else...that replacing the unit temporarily, as you did isn't a guarantee that the problem isn't elsewhere in the system.
>He also said he would be willing to take apart a unit and clean/inspect if it is ultimately the problem as suggested by the diagnostics. 
>As to the problem below it turned out to be the transmission mounts allowing for engine/trans movement on acceleration. Replacing these was like night and day in terms of how the car  felt and I was again amazed at how little you notice when the problem slowly creeps up on you.
>Driveshaft bearing was also replaced somewhere along the line though this wasn't the primary problem.
>Same thing with tuning...it ran much better after a careful tune up and I never would have guessed it needed it.
>The squeel was the AC clutch fan moving with the entire drivetrain (if I remember).
>The mounts were flat as pancakes.
>I'd check tranny and engine, diff mounts first.
>Good luck.
>Richard
>
>-----Original Message-----
>>From: keithbedard at verizon.net
>>Sent: Mar 30, 2007 8:07 AM
>>To: rguzz at mindspring.com
>>Subject: Audi driveshaft shudder/vibration...
>>
>>Hi Rich,
>> 
>>I recently found your 2004 post to Audifans.com, which is EXACTLY the same two problems I have with my 1995.5 S6:
>>1.  shudder, or vibration, mostly noticeable on early take off in first or second. 
>>2.  a squeal that  sounds like fan against radiator while decelerating under load.  
>>
>>Your post from 2004 is here:
>>http://coimbra.ans.net/pipermail/s-car-list/2004-January/024473.html 
>>
>>What did the diagnosis on your car 2.5 years ago?  Tomorrow (Saturday), I will only have a couple of hours to try to diagnose the culprit...  
>>
>>Thank you,
>>Keith Bedard
>>Templeton, MA