A4 B6 1.8TQ warm tiptronic, park/neutral-> drive jerking

[Type_Audi]

I've been noticing lately that our 04' b6 1.8TQ is jerking pretty hard when shifting from park or neutral into drive when the tranny is warm. There is no issue when shifting from park/neutral into drive on a cold start, everything is smooth.

Searching hasn't turned up a clear answer but I do remember someone mentioning an issue with the brake pedal switch. I know that switch is an input to the tiptronic module (at least vag com shows it) and I'll check it's operation when I get a chance.

I changed the filter/fluid about 30k miles ago (has 105k miles now) following the proper procedure and didn't notice any problems for 1,000's of miles afterwards. The battery was changed once which reset tiptronics shift pattery learning but thats been a long long time ago.

Could this be an issue of the fluid being low? This fluid expands when it gets hot so if the fluid was low issues should show up on a cold start, not when it's already warmed up.

Any ideas are appreciated, I don't want the transmission to tear itself apart.

[Type_Audi]

Is there anybody out there? (to those pink Floyd fans)

[vinny.dtw]

Seems like you did a lot of what most would do, and that is servicing the tiptronic tranny itself. It isn't pulling any codes correct?

If in the event you need a new tiptronic trans, I have one for sale for very cheap. And it's in great working condition.

[Type_Audi]

Seems like you did a lot of what most would do, and that is servicing the tiptronic tranny itself. It isn't pulling any codes correct?

If in the event you need a new tiptronic trans, I have one for sale for very cheap. And it's in great working condition.

Vinny,

Thanks for the offer but I believe I found the problem: not enough fluid.

When I did the service I thought I was careful to make sure everything was done correctly, i.e. keep the fluid under 40 C, go through the gears, etc...

When I jacked it up today and pulled the transmission fill plug, I was able to get another quart and a half or so into the transmission before any overspill occurred. I don't see any leaks around the transmission so I must have just not put enough in the first time.

In my opinion the ECS tuning kit should come with 7 quarts, not 6 quarts of fluid.

Hopefully this was the issue, i'll drive it over the next couple of days and see how it goes.

[Type_Audi]

We'll, turns out the transmission was overfilled by about a quart and a half. This explains why the jerking symptoms were worse as the fluid warmed up. This fluid, seriously expands with temperature. I very carefully monitored the temp and opened the fill check plug at 35C as the instructions say, it drained fluid until 39C then I replaced the check plug. I'll give it a test drive today and hope for the best.

I'll definitely do a TCM reset so the tranny can re learn the shift points. hopefully nothing was damaged.

[Type_Audi]

OK, so here's the status update on the 04' 1.8T A4 Quattro tiptronic fun (~106k miles).

After I made sure the transmission level was correct yesterday I let the car sit overnight with the battery disconnected. I wanted everything to reset, the TPS, TCM, everything. This morning I plugged the battery back in, did the TPS adjustment via vag-com and proceeded to drive. Shifts were smooth going up and down in D mode, then, once the transmission fluid temperature rose above 35C the the downshift from 5 to 4 started getting rough again. This rough downshift from 5 to 4 only occurs if you let off the gas and let the car coast (overrun) to a piont where it must downshift because the vehicle speed is too low (i.e. around 35 mph it goes from 5th to 4th). If however I'm in fifth gear, with 15% throttle and manually shift down to 4th, the shift is perfectly smooth. This rought shift only occurs when you let off the throttle, which seems odd to me since the tranny is barefly under load. All other shifts, up and down the entire range, are perfect.

I've scanned for codes in Vag-Com, everything scans clean. At this point I'm wondering what the problem is. In almost every post i've found on AW, Audi-Forums etc. someone is throwing a code. My gut feeling is that it's electrical related since this the issue only occurs on overrun (foot off the gas). It's as if the tranny doesn't know my foot is off the gas and shifts incorrectly as a result (wouldn't that throw a code?).

A couple specific questions.
1. Did I definately reset the tranny after leaving the battery disconnected?
2. Is this the problem? (http://forums.subdriven.com/showthre...hard-shift-5-4)

Any advice is greatly appreciated, I avoid the dealership at all costs (because it costs!).

[nofearhawk]

Soooo you added a quart and a half, and then two days later realized it was overfilled a quart and a half? I'm just trying to follow your troubleshooting.

[Type_Audi]

Soooo you added a quart and a half, and then two days later realized it was overfilled a quart and a half? I'm just trying to follow your troubleshooting.

I had overfilled it when I originally changed the fluid over 4 months ago, I just recently checked it and found 1.5 quarts overfill.

[Type_Audi]

Continuing my saga with this 01V (ZF 5HP19) tiptronic I believe I've finally nailed down the problem to the N91 solenoid which sits on top of the valve body (VAG part number 01V 927 333 C). I'm still not throwing any codes and I actually had the dealer check the car today, they said they have no idea what is wrong unless they tear it apart (also quoted $5k+ for a new tiptronic + labor).

I stumbled across this thread that had exactly the same symptom I am having. This is the only link I've come upon after weeks of searching that explains the exact problem I'm having. Unfortunately it means I need to pull the valve body apart but this can be done no problem without removing the transmission.

I also found a great resource for tech info and parts for ZF transmissions here.

Once the parts arrive I'm going to beat this ho back into working like a good little transmission and try to take some good pictures for everyone in the process.

[Type_Audi]

FYI, the solution to this problem was found. See the discussion here

[Type_Audi]

After replacing the N91 solenoid on top of the valve body of my 01V tiptronic, all problems have been corrected.

As an FYI, the valves can be purchased individually from a number of sources. In some forums it's mentioned that you have to purchase all 7 as a set, this is not true.