Hello All

Forgive me if I am posting in the wrong place and redirect me as needed.

I have a 2007 A3, 3.2 S-Line. I've owned it for about 4 months having purchased it used from a dealership. AT, 53k miles. Great, fast little car.

After driving it for a couple of months I noticed the following- After driving enough to get the car well warmed, when coming to a stop at an intersection or pulling into a parking space, there is a very noticeable "thunk" as the car comes to a complete stop. It is both a noise and a noticeable feeling; gliding to a smooth stop with my foot on the brake at the end of a highway ramp, just as the car is nearly stopped, it feels like the transmission "clunks" into a lower gear with a "thunk" and a lurch that is felt by anyone in the car. IT is worse after driving at highway speeds for perhaps an hour or more.

The best way I can describe it is, if you were driving a manual shift and let the clutch out without stepping on the gas, the car would just lurch and cut out. But the car is an automatic. The engine doesn't quit.

The dealership has it now and they can reproduce the problem but there are no error codes.They are doing some test, warming the car up from cold to check the fluid levels as there is not a dipstick to check the transmisson levels. There is no leakage.

The car runs very well and there are no other issues. I am just concerned that there is something very wrong with the transmission.

I welcome any thoughts on this issue and am grateful for your advice.

 

It could be a CV joint on one of the 4 half shafts or possibly one of the 2 CV joints on the main drive shaft. Look for any torn or ripped open rubber boots on both ends of all those shafts. If you find one, I'd replace it.

Also, while 53K isn't a lot of miles on those transmissions you may want to entertain the thought of a fluid and filter change on the trans just to be sure.

 

Many Thanks Dave- The car is still in the shop and they are checking fluids but also there was a torn boot which they are replacing. I wonder if the CV joint that the boot covers is ok. Would they inspect and lube that while they've got all apart? Thanks again!

 

Since you have to remove the shafts and disassemble them to replace the boot, would expect them to inspect the joint (it will have to be thoroughly cleaned and repacked with new grease) so I would hope that they would see any wear spots that might cause any clunking issues.

 

Thanks again for help and education about my Audi. I got my car back from the shop today. Apart from an oil change etc, they did in fact replace the torn boot (along with cleaning and inspecting and repacking the joint. They also checked the transmission fluid level and topped it though they said it wasn't alarmingly low. They tested it and felt it was corrected. I tested it but only in driving home which wasn't really long a long drive but perhaps long enough to get hot.

The situation is much improved. Coming to a stop I can sense a very mild "nudge" in the drive train but it may be really normal and something I'd not have even noticed if I wasn't anticipating it.

They said the joint looked fine and felt that it wasn't the problem I was describing. I am glad to have the boot replaced though as it would have become a problem soon enough. I am inclined to think that the joint being "open" and probably dirty and not well lubricated was as much if not all of the problem (over the transmission.) I am posting this detail in case anyone is searching for the same problem. Thanks for your obvious expertise and for taking the time to reply.

 

That little nudge you feel as you are coming to a stop is the transmission downshifting to 2nd gear just as you scrub off the last mph or two. This is normal. If the fluid was a little low it could have been causing a bit of a hard downshift.

Getting that boot fixed is definitely a plus. You can ride them for a short while like that but letting water and dirt get in there is going to kill the joint faster.

Drive it a bit more and make sure the problem has gone away with the fluid top off. However, I would urge you to have the transmission fluid and filter changed sometime soon. Changing the fluid on Audi transmissions, even though Audi says it's not necessary, is just good sense. This will flush about half of the fluid from the system and help remove any normal wear particles that filter has picked up improving fluid flow. It's impossible to flush all fluid out without removing the trans and torque converter which is overkill and EXPENSIVE.

Parts and fluid (you MUST use the Audi/VW Synthetics or equivalent) will run about $200 (you can get kits from Blauparts.com) and can be done by just about any shop. Although I recommend using a shop that is familiar with German cars just to be safe. I change my own in my 03 A8L and while I'm an UNcertified Porsche/Audi/VW mechanic when I'm not an IT Geek (my day job), anyone with a decent amount of automotive repair experience and a good set of tools could do it. I do NOT recommend a novice do it though.

Anyway, glad you got it fixed. That's what we're here for.