jseklund

So, many of you probably have read my past posts about changing transmission fluid. I am the LAST person who believes that changing any fluid can cause a problem, but this thread will likely be interpreted as such by some people.

I have a 2004 A6Q 2.7T with 288,000 miles on the odometer. The car has had ATF changes at 93,000 miles when I bought it and every 50,000-75,000 miles since that.

I am roughly at the 75,000 mile mark now (I forgot about it, things have been really crazy this year) and a few weeks ago I noticed that between 35-40 MPH my RPMs would rev just a little if I was under light throttle, and sometimes the car would "growl" or vibrate a little in this range, randomly. I wasn't sure I had a transmission problem, but figured it was time to change the transmission fluid anyway, so I'd take it apart and see what was in the pan. If this was a problem, it seemed to be very minor. I actually think it may be a vacuum leak or throttle issue...

So last night I changed the fluid. I used Amsoil ATF, which I've used on 3 different cars and on this car for all of its ATF changes. When I dropped the pan, there were no metal shavings at all on the magnets, and the fluid was still red. I did note the fluid seemed to be ...I don't know....greasy? Watery with oil in it? I don't know how to explain it, but it was due to change it. There was also a thin layer of black crud on the bottom of the pan and on the magnets. It was almost like thin black grease.

I cleaned it all up, put a new filter on, put it back together, filled the pan with the car level. I then started the car, ran it through the gears while filling and repeated running through each gear, including using the tiptronic to go through individual gears, until the car was at 38C and fluid was dripping out in all gears. Normally when I've done this, fluid will pour out if it is over full, but it kept coming out in a small stream, and when that stream stopped I would give a pump and it would start coming out again, which indicated that at all times I was full and adding even a little more would cause it to overflow...

Now, since the change, when I am in under low throttle in 1st or 2nd gear, the engine revs way up when it is about to shift. It is USUALLY happening in 1st gear, but sometimes it shifts fine in first gear. It usually shifts fine from 2nd to 3rd, but sometimes when 1st shifts into 2nd fine, it revs going into 3rd.

It sometimes downshifts harshly now too.

Before the oil change, I didn't have any of these problems.

Any thoughts on this? Did I maybe not fill it correctly?

Also, prior to last night I used the Vag-Com and the ECU and TCU were free of any codes, but the ABS had code 01119 - which is a gear recognition fault. Whenever I look this up, the only instruction is to look to the TCU for codes, but there are none. Beyond that code, nothing is coming up in Vag-Com.

Any thoughts would be greatly appreciated. Thanks guys.

jcman

Might be a good time to check the front differential fluid for cross contamination, seals are the only thing separating the two fluids.

indoor

I would have taken off the valve body and clean the solenoid while the pan was down. The 'black grease' you found on the bottom of the pan is probably clogging the input speed sensor enough to give you problems. A wild guess, but if the problems get worse you might want to look into it... https://www.audiworld.com/forums/a6-.../#post24577920

jseklund

Guys, thank you both for the responses. I would like to do what you both suggest. Obviously, at 288,000 if I can save my tranny from having difficulty by dropping the pan or replacing the seals, it's a win for me.

I am going to limit driving this around for the next few days, but I still need it for work tomorrow and maybe a little on wed. I will probably take Friday off and drop the pan again, etc.

I am thinking I can suck the fluid that is in there out with my fluid extractor so that I can save most of it. On the other hand, maybe it mixed with what was left in the tranny and I'm better off just biting the bullet on the wasted fluid to get even more of the old stuff out...I have plenty of fluid left for a second change.

I will look at my Bentley to learn about the seals and the valve body, but thanks for pointing me in the right direction. I took a quick look at that thread, and my pan wasn't that bad - but that grease at the bottom of the pan looks similar to mine, only I didn't have nearly that much on my pan...just a thin coating over the pan, no buildup like in that photo. I'm still going to drop it again and take another look.

clancy

with that many miles I would not re-use the fluid. The cleaning properties are likely what has upset the sludge (whatever) that may be contributing to your issues. It is doing its job, drain out and discard. Let more new fluid continue cleaning. I would certainly do the valve body service, then more new fluid and even another new filter.

jseklund

Well, I was driving last night and the car started jerking more, then my check engine light came on. I had a torque converter code that I looked up on Ross-Tech and found that the first cause listed was low fluid levels. Since I didn't have these problems before the fluid change, I'm guessing this is most likely my issue...I'm going to top it up today (if I have time) and if the problems don't go away by this weekend I'm getting a new filter/gasket and doing the entire job over so I can pull the valve body and inspect a little more deeply....

jseklund

This is the way I was leaning....I don't think it was worth re-using things when I was doing the job over...just get the junk out and put fresh in. If I can get another 100,000 out of this car I would be thrilled beyond belief...and if the transmission is still healthy and this is just a fluid issue/cleaning issue....then I don't see why I couldn't. The car runs pretty well...it's older and has little annoying problems, but it has been very reliable (knock on wood) and I trust it will keep going. As long as this isn't a sign of a bigger tranny issue....tranny and turbos are the only things that I think would put this car in its grave at this point.

I do have a relatively large oil leak at the front of the engine also. At first I thought it was the turbos, but looking further back, the turbos look dry. The intercooler pipes at the front of the engine are COVERED in oil, lots of it, and looking from top it looks like their is oil crusted all over the top timing belt cover. I'm guessing I have a massive valve cover/cam seal/cam tensioner seal leak and those need to be replaced soon. My breather hose went last winter, so I'm not too surprised if that caused this issue and it just took time to get bad.

jseklund

Just an update - I checked my car today. Upon inspection I saw the pan was leaking, just a little. I didn't torque the bolts enough...I am always afraid of breaking one, but I didn't realize that even with light pressure, I was using a cheap torx bit and it was twisting.

Then, I checked the level....and despite the fact I've done this at least 5 times on various Audis, I still managed to screw up the fluid level. It was WAY low. I was tired the other night when I filled it, and didn't pay attention to how much went in, and must have not hooked the hose in the pan right and it appeared to be overflowing but wasn't. I was easily 5 quarts low.

After filling properly and test driving, the car seems to be running much better and all of the revving and hard shift issues seem to be gone. Even the original issues before the change seem to be better....so I'm hoping that does it.

I may still drop the pan in 10,000 or so anyway just to do it again and clean the valve body...

clancy

Five low, wow. Glad you figured it out. Beats messing with the valve body.
Mine has the bad O ring in the torque converter. I have changed the fluid and filter four times in the last 80,000 miles. Each time the lock up gets a little better. I know it will not fix the issue, but the frequent changes have gotten it to at least lock up when the trans is still cold. Did not lock up at all when I started. Point is the loss of only 1-2mpg is not worth pulling the trans. And the fluid changes are likely helping prolong the life of an overtaxed TC. I understand if the lock up does not work that the system works harder with all the slipping, etc.
Anyway, I am now alternating, full fluid services wth filter one time. Then the next I just drain the few quarts that come out by pulling the plug only. This is so easy since I don't have to drop the pan. I am hoping that by doing this every 10,000 miles or so that I can keep my trans alive until something else kills the car.

jseklund

I hear that. My tranny has treated me well, and I hope it continues to do so. I know the sludge in the pan wasn't a good sign, but there isn't a lot of it and I think I went past 75,000 miles since the last change...the fluid was just old as could be. Maybe if the car was at 100,000 I would have gotten away with it, but at 288,000 ....well...you can't look a gift horse in the mouth.

I had a Pontiac Bonneville a while back that started having some tranny bucking about 35,000 miles after a fluid change, at around 115,000 miles. I hoped I could fix it with fluid and changed the fluid/filter again and drove for a while. Then it got worse. A couple weeks after that fluid change the car lost the tranny and would just refuse to move. I had to park it in a parking lot overnight. When I cam back it would move again and I got it home and dropped the pan. The fluid was no longer red. It was pure silver. Not that I really needed to take it apart to know the tranny was toast...but I was still hopeful.

The point of the story is, I don't tend to think that fluid will "fix" a tranny anymore and I was starting to worry. Hopefully this fixes things for a while and I didn't do much damage with the low level...