# 2001 Audi TT 225 Quattro won't reverse while turning



## Chuck850 (Jun 7, 2009)

I asked this over in the technical Quattro forum, but wasn't getting much response there, so I thought I'd try here with my fellow TT owners. I'm looking for some guidance on how to diagnose an issue with a 2001 Audi TT ALMS 225 Quattro I bought for my wife. It had 60,000 miles on it and had not had any record of the Haldex being serviced. 

Went ahead and had the service (filter, fluid, etc) and I don't know if this problem existed prior to service. A mechanic did this for me (I didn't do the service). 

The problem I have with it is that it will reverse straight with no problems. If I reverse on a turn (right or left), it feels as if the car slowly builds resistance as it reverses, until the point where it bogs the engine down and feels like something might break if I force it. It reminds me of a spring winding tighter and tighter or hydraulic pressure building as I turn and reverse.

The second symptom I've recently notices is that the inside rear will slips when turning in a tight circle going forward (as if the differential isn't functioning properly as well).

Any advice would be appreciated on how to troubleshoot, or opinions on a diagnosis. Thanks!


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## PLAYED TT (Oct 17, 2010)

The haldex controller maybe? Is the car stock?


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## Chuck850 (Jun 7, 2009)

It's all stock. No mods at all (wife's car). 

Would the haldex cause the rear differential to change side to side power distribution or lock up the differential so the tires slip? I assumed the haldex controls power distribution front to rear, not side to side, but I am not completely familiar with it and may be wrong about how it works.


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## Chuck850 (Jun 7, 2009)

I have a little more data. Spent some time testing today. Was sitting in the garage with the engine running for about 10 minutes, using my VAG-COM to check error codes, look around at controllers, etc.

I disconnect the VAG-COM, put the car in reverse and turn as I'm backing out. Works fine. Going forward in a circle, works fine.

This evening, after letting the car sit all day, I immediately start it, turn, and the rear wheels aren't turning again as expected. Backing up while turning gives me the slow resistance I mentioned earlier. The car goes back about two-three feet and won't go back anymore.

If I just stopped, and waited 5/10 seconds, then I could back up another two to three feet. It feels like some hydraulic pressure builds, but can't release fast enough to compensate. Sitting a few moments seems to allow the pressure to equalize, then I can back up again.

Any ideas would greatly be appreciated. I'd hate to start throwing parts at the problem since everything back there is pretty expensive, and unfortunately alot of repair shops seem to take that tack at problems, so I'd like to have some idea what's going on before I take it in.


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## PLAYED TT (Oct 17, 2010)

Check the wiring on the controller to see if it's loose.


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## JohnLZ7W (Nov 23, 2003)

Had same problem with my wife's car, swapped the controller to my car and the problem followed. New blue controller fixed the problem. The aftermarket controllers are about $900 but you can probably get a used controller from someone else who's already upgraded. The swap is pretty easy.


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## Chuck850 (Jun 7, 2009)

Thanks. Now that it's Christmas break, I'll work on getting this fixed. I also came across this interesting read that also describes my problem. I've written Haldex for more information, and I'll post here when I get it. In the mean time, has anyone else heard of this? 

http://www.audittcca.com/discussions/auditt/00005299/conversation_view?b_start:int=0

Basically, the post indicates water can get into the coupling and mix with the oil, causing the issue. Apparently there are vents in the coupling and supposedly a suggested fix from Haldex.


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## ssweetd (Jan 17, 2006)

*any updates on this?*

we just purchased a 2003 one-owner 6-spd 225hp coupe with factory 18's from audi of silver spring in md for my girlfriend. it shares the garage with my '04 s4.

i think i am seeing something similar.

after we got it home to pa, i drove it later that week and noticed that the car seemed to skip when turning turning tightly in forward or reverse. as soon as you ease up on the steering angle, the wheel skipping goes away.

so - is this normal on tt's because of the short wheelbase and in our case, bigger wheels? i've had a service advisor say that it is (though he had never heard of water in the haldex fluid being an issue), and a sales advisor say he has seen them do it also.

does anyone have a definitive answer? thanks!


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## PLAYED TT (Oct 17, 2010)

There are people who run 18's and 19's and I have never heard of the wheels being a problem.


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## ssweetd (Jan 17, 2006)

Had the local dealer change the Haldex fluid and filter. Of course, since the car was warm and in the shop, it did have the symptoms when they were finished with it.

But when we went to pick it up later that night after it was sitting out in the cold, the 'hopping' was there again.

Is this a controller issue as mentioned in one of the posts above?


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## JohnLZ7W (Nov 23, 2003)

Yes, needs new controller.


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## ssweetd (Jan 17, 2006)

John - Thanks.

Could that be true even if it is throwing no codes?- I have the vag-com software and it showing no faults for the haldex.


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## JohnLZ7W (Nov 23, 2003)

Yes it's possible. Run the output tests and listen for the pump activating, if it doesn't then it's most likely the controller. You could probably get a really cheap used one off of someone here that's upgraded to a blue/orange controller.


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## ssweetd (Jan 17, 2006)

Hate to ask but what are the steps/process for running that and can the wheels be on the ground?


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## Greg_CabinKrew (Jan 7, 2005)

I hate to dig up an almost 4 year old thread but I feel it was on to something and I have the exact same problem with a bit more info. 

I started noticing that if I would reverse out of my garage and attempt a 3-point turn, the rear wheels would lock up and skip. If I reverse slow and straight, I wouldn't have an issue. It was always more susceptible to this in the morning. If this occurred, even after driving forward and straight, I would lose a lot of power and feel like the e-brake was still on or some kind of drag. When I would go over a sharp peaking hill or a bump, the ESP warning would flash on the dash, the car would bog down, and then like magic the car would be free from the issue. After a while though it would take a few dips/hills/bumps to unlock until nothing would other than time. It got worse and worse until last month, it started getting really bad just a few mins from my house and my transfer case grenaded. I had a new transfer case installed, had my rear diff fluid and filter changed, new tires to get my tire size ratio down to an acceptable tolerance (less than a 1/4 inch difference between front and rear which was WAY out before incident) and an alignment. When I drove away from the shop, the car drove AWESOME but I noticed a lot of road noise. I figured it was from the cheap tires I bought. Its definitely not the tires. I've driven it almost 800 miles since the repairs and the noise has gotten worse. Sounds like the rear diff is whining. That whine is now, as of yesterday, accompanied by a rhythmic knocking from the rear as well. Sounds like a peg money wheel from a carnival/bull roast. It gets faster the faster the car goes and slows up as the car comes to a stop. I've read so many conflicting ideas or suggestions from all over the internet. I even once in a while feel the reverse resistance at a sharp turn again although not nearly as often nor severe. Does anybody have anything to add or have any idea what is going wrong? Its an 04 TT 225 with 78K miles on it. I just dumped a ton of money into it fixing the transfer case and I'd like to get to the problem once and for all. I really wanna sell it but can't in good conscience do so in this state to a private buyer and a dealer with lowball me big time. Please help! Thanks, guys!


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## hunTTsvegas (Aug 27, 2012)

When mine started to act up and make a similar noise, I pulled the fuse. Noise went away and binding/resistance quit. Got me in the area I needed to focus in. From there it's pre-charge pump or controller (provided oil and filter have been changed at the proper service intervals).


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## Greg_CabinKrew (Jan 7, 2005)

It's funny you say that because not 10 mins ago, I pulled Fuse 31 and ALL of the symptoms went away! My car hasn't been that fun to drive in over a year. My buddy just told me if that's the case, it's more than likely the pump. If so, the strain from the dry dragging diff caused the transfer case explode. Thanks for the great advice! I now finally have a focal point to work on


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## hunTTsvegas (Aug 27, 2012)

Sure thing! Glad it helped isolate the problems. Do some searching as I recall reading some people successfully using reasonably priced Volvo pumps in place of the extremely expensive pump from the dealership.


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## Greg_CabinKrew (Jan 7, 2005)

I have read before that the Haldex systems in Volvo's are very close to those in Audi's...thanks for the reminder!


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## ssweetd (Jan 17, 2006)

Sorry to hear of your issues. I had posted about my rear end issues a while back on this thread. I have posted on a bunch of other threads over the past year or two, also, as I tried to figure out what was going on.

To make a long story short, our issues (inconsistent rear end binding) began soon after we purchased our one-owner 2003 from an Audi dealer. We moved half-way across the country soon after and had no recourse.

It was suggested to me by users on here that a bad controller was the cause, but at that time, stock controllers were harder to come by than they are now, and much more expensive. In addition, after we moved, I no longer had a local garage to do the work. The car was driving 'fine' other than parking lot type turns, and quattro worked great so we just dealt with it for 4 years. No Audi dealer could tell us what the exact issue was.

But about six months ago, we started hearing a whining from the rear that began at moderate speeds when off the throttle. This began to get louder. I replaced the rear end with a used one from Shokan (controller, pump, haldex, diff) and we are finally running fine now.

I believe my issue was a controller that eventually became 'stuck' in a way that had the haldex keeping the rear diff engaged full time. This eventually caused wear over time, though it gave the car a nicer rear drive feel. Maybe if i would have replaced the controller right away, I would have been ok. I still have the old controller and am going to check the valve in it at some point.

Before they reach us, I think a lot of these cars have been bought used by people who have no idea of their service needs. I am guessing that they do not know the transaxle, haldex diff, and rear diff all take different fluids, too. As others have said at this point, the haldex and rear diff on their own are mostly bullet-proof - it is the controller and the pump that are the start of issues.

Let us know how you make out. The R32 and euro forums have a ton of examples at this point.


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## Greg_CabinKrew (Jan 7, 2005)

Glad to hear you figured your issue out. Mine has been going on for about a year and a half now. I have even noticed a dip in gas mileage but didn't associate it with the rear until I pulled Fuse 31 and felt how free the car was driving. A buddy of mine has a rear he is selling me. I plan on cleaning out his precharge pump and servicing as much as I can before throwing it onto the car. Now if I can only figure out the damn incessant clunking from the rear when driving on back roads and bumps I may actually fall back in love with the TT! Hahaha! I have a feeling it's a spring(s) from my cheap ass coilover set I have...I may have left the perches out to lower the rear more and that's why the springs flop around...


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## ssweetd (Jan 17, 2006)

Greg - I think your issue is the first I have seen where a transaxle went bad, too. I hope ours did not suffer at all. I never noticed a drop in gas mileage. We did a lot of highway miles and I was always surprised at how good the mileage was. I did have our transaxle fluid changed as a preventative when our 'new' old rear end was put in.

I know what you mean about 'falling back in love'. When that rear end went in and the binding was finally gone after four years of ownership, it was a great day! My OCD gets worse every day as I get older, and though we have been relatively lucky with ours, at 123k, I worry. But in the meantime, to make myself feel better, I did just take out the back seat uprights and the CD changer and put in an iPod/iPhone connector. Also had the headliner replaced with a black suede-like material since it was sagging.

Make sure your friend's rear end is compatible with your year. I believe that at some point in or right before 2003, there were some changes to the controller, at least - I could be wrong.

Good idea about taking a look at your pump when you get it. I had thought about doing that, too, but I didn't, only because the rear end came with a six month warranty. I wish Audi would troubleshoot these issues and replace individual components rather than just saying, 'you'll need to hand us $3500 for a new installed rear end'.

It was nice to see when these threads began showing some resolutions. It was so frustrating in the past looking at the early R32 and TT threads where the issues first came up but no one knew why things were happening.

This is a great community and an invaluable resource.


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## Greg_CabinKrew (Jan 7, 2005)

I agree...forums like these with actual results will help save a ton of headaches and money for fellow members down the road...thanks again for all of your help, guys! :thumbup:


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