DeafM5

I recently got an 04 Audi A8L with 164k miles on it. I know the history of the car since 37k miles. It is due for transmission oil drain and fill along with new filter. While I am at it, I will also replace the bridge adapter seal, mechatronic seal, and other sealing pieces. Now I have an issue with transmission where I can feel first gear clunk when I accelerate or "lurch" maybe during acceleration. Is that clunk related to valvebody being worn out or not performing correctly? It really takes away the luxuriousness from the Audi and passengers can feel the flaw in shifting characteristics.

Jack88

It could be that worn seal, called the pan gasket seal. I will say my car tends to lurch upon takeoff after a stop sign a bit, being like it waits to kickdown from second until after I have started to push the throttle. According to ZF, at a certain point, the mechatronix has adapted to the changes as it ages and that even changing the solenoids won't fix the issue. I will also say that although my pan gasket seal was clearly warped, it did not solve this issue.

DeafM5

That is what I have right now on my transmission. I do not like how the transmission lurch especially it is more pronounced in uphill roads. Do you think if resetting adaption after new solenoids installed will improve?

I recently performed solenoids replacement, seal, new pan gasket, etc on a 6HP19 on my X5. I can say that now the transmission is shifting like it is a brand new transmission. I can't even feel the shifts. That is how much the transmission improved after the service. I have an ability to reset the adaption on transmission after the service if it is needed for my audi.

Jack88

You can try that, I opted not to replace the solenoids as it is something you learn to drive around, provided it isn't too bad. Mine is subtle enough you'd not know it wasn't normal if you didn't know any better.

MP4.2+6.0

Make sure fluid level is correct first, plus run a transmission adaptation including the driving cycle alongside. After that, yes new solenoid set may smooth out but it is a bit of a crap shoot. It did bring my 2006 2006 W12 tranny back to like new at around 100K miles.

DeafM5

I drove my audi little bit hard. I noticed that the downshifts were harsh and few flares on 5-4 shift. It may point to valvebody issue.

MP4.2+6.0

Mine flared on 6-5. That was when I did the solenoids in the valve body. Pretty exacting work on difficulty scale, but if you did the BMW w/ 6 speed, presumably essentially the same. See pictures in this thread: https://www.audiworld.com/forums/a8-...ssion-2866629/ Importantly, note my discussion and pictures about the rubber SEAL that connects Mechatronics valve body to the transmission case. I found out about that from some deep dives on BMW boards. I suspect that was the likely issue, but new solenoids gave me more confidence it would be once and done. It was.

I got the solenoids from Erickson Imndustries in CT. http://www.erikssonindustries.com Back when ZF distribution in USA was organized by car manufacturer, they were the lead Audi one. With the ZF number plate/3 digit code they ordered up the exact kit--even for my really low volume W12 variant. One thing they did not get right was the gasket. BMW's use a different pan and bolt pattern than mine did, and I think that is probably the gasket they sent me--a metal sandwich type. Audis use a paper one, or at least mine does. Pain in butt to keep in place as you get first Torx bolts into pan. If you do it, a tip is check gasket general fitment before you start to tear down anything to avoid a fire drill.

DeafM5

I had my audi up on the lift for exhaust system repairs. $300 for 2 flex pipes and 2 exhaust sleeves installed. While it was in the air, i inspected how hard to reach all bolts on transmission pan, and it appears that I will be spending little extra time to get to a couple bolts because of subframe or metal frame in the way. Downshifts slowing down are nott too bad, but taking off from a dead or rolling stop. As I initially accelerate it seems like it goes into neutral, the engine rev's and then it slams into gear.

I wonder if my valve body is worn out? I do know that the valvebody is original and have not been touched.

Jack88

That metal bar in the way comes out pretty easily, held in with 4 bolts and it's not under any stress unless you got one tire up in the air by itself.

DeafM5

Awesome. I took a look underside real quick so I did not see those bolts. I just wanted to make sure my exhaust system were repaired correctly.