Strange problem with hard shifting on 3.0l

[boqishah]

I have a 2003 a6 3.0 which bangs into each gear - no CELs. The car has gone through the whole flooding of the TCM thanks to the shitty drain holes issue with these Audis. Initially, after replacing the TCM, the car ran fine with smooth shifting. After about a couple of months , I started the car to back out of the driveway, and as I put it into gear it banged into reverse and banged into first and second all the way to fifth - it even downshifted with a bang. The shifting switched between flawless or horrible banging for a few days and now it always shifts with horrible banging. I have reset the throttle body, change the oil and filter, replaced the valve body etc. Please help! I believe it has something to do with the over engineered throttle body. One more strange thing is that my auto says "depress clutch pedal to start" on the instrument cluster since the flooding of the TCM.

[Scotty@Advanced]

I have a 2003 a6 3.0 which bangs into each gear - no CELs. The car has gone through the whole flooding of the TCM thanks to the shitty drain holes issue with these Audis. Initially, after replacing the TCM, the car ran fine with smooth shifting. After about a couple of months , I started the car to back out of the driveway, and as I put it into gear it banged into reverse and banged into first and second all the way to fifth - it even downshifted with a bang. The shifting switched between flawless or horrible banging for a few days and now it always shifts with horrible banging. I have reset the throttle body, change the oil and filter, replaced the valve body etc. Please help! I believe it has something to do with the over engineered throttle body. One more strange thing is that my auto says "depress clutch pedal to start" on the instrument cluster since the flooding of the TCM.

Sounds like there is an issue with your wiring harness, or possibly the new TCM, as with a TCM present the message "Depress clutch pedal to Start" should not be displayed. The connector to the TCM could have corrosion on it as well.

[Vinnie981]

i agree with scott.....but the fact that it says "depress clutch pedal to start" in my eyes means that you didn't by the right TCU or it is coded incorrectly. Whats the # on our TCU? That will help a whole lot

[boqishah]

The original TCM was 4b0 927 156 FF, and one I bought was 4b0 927 156 AJ from a wrecked 02 A6 3.0 Q (if I remember correctly - I will pull out the TCM tomorrow and confirm the numbers). I read on a few forums that FF and AJ were interchangeable. Anyway, I had a shop (which had a vagcom) do the swap, and it worked perfectly for a few hundred miles before it started to do the bone crunching shifting on and off. Scott may be right about the wiring harness - I have suspected that for a while but have not replaced it yet. The TCM was never coded just swapped and reset.

[Vinnie981]

IMO thats your problem.....When my 2002 Audi A6 3.0 battery drains got clogged and flooded my TCU and CCM, I replaced my TCU with a 2004 Audi A6 3.0 TCU because in my eyes the trans is the same along with the ratio's. Both had sport mode and everything. Well it worked but shifted hard as hell. I returned that TCU and finally found a matching original TCU which was 4BO 927 156 FF. Worked like a charm. The TCU look 100% identical inside and out. Only difference I believe is Coding and Software.

Anyway after all that my 3.0 threw a rod a year later lol.

[boqishah]

I found a FF TCM from an 03, and it should be in my hands on Monday. I will post after I do the swap. Thanks for the help!

[boqishah]

First of all, the TCM I had in there was 4B0 927 156 DE and not AJ which is interchangeable with the FF. I get the FF and plug it in, but no luck with either the "depress clutch pedal" bullshit or the shifting - with the FF it goes into limp mode and does shift at all. I swap back to the DE and it starts to shift again but hard like before. I think the issue with the hard shifting is the throttle body because I plugged in an obd 2 and it gave me real time throttle open percentage. Without having the gas pressed the throttle was at 11.5% and at full throttle it only went to 85%. I tried to do the manual reset but didn't do anything.