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Hello,
A while back I had some problems with some noise when going backwards. Lo an behold, the problem appeared when going forward aswell. Long story short, got the error when I was going in 3rd, then the transmission error popped up and downshifted back to 2nd and got stuck there, won't go in 1st aswell. The only way I was able to get back home I had to start in 1st,go into *manual" then shift to 2nd, raise RPM and then instantly shift to 4 and keep RPM around 2.5-3k so the vehicle doesn't downshift or try to upshift.
Vehicle, A4 B9 2 TFSI, 185kw, Quattro. 2018.
Today I removed the gearbox, the flywheel is done, noisy and there's something loose inside it. Removed the mechatronic, oil in there was clear, then removed the oil pump, black oil with a lit bit of rubbish fell out, From diagnostics I can tell that the both clutches lose pressure and then the shifting becomes rough and that the pump: Emergency run since calibration was not performed yet everything was done as it should.. Can a faulty flywheel cause this or is this more of a mechatronic problem? Guessing the 2nd option. Going to dissasemble the whole transmission tommorow and hope for the best. I'm just curious, maybe someone ever ran into something like this. The errors that came up were these:
Address 02: Auto Trans (J217) Labels:| 0CJ-927-156.clb
Part No SW: 80A 927 155 BE HW: 0CJ 927 156
Component: 0CJ 20TFSIRdW H05 0003
Revision: --H05--- Serial number: 0000001665 CVN: 86AE417B
Coding: 000001
Shop #: WSC 05761 780 00200
ASAM Dataset: EV_TCMDL382021 002027
ROD: EV_TCMDL382021_AU49.rod
VCID: 6DD17CB3BC91F7FB18-8038
MTF pump:
Subsystem 1 - Part No SW: 0CK 927 152 AA HW: 0CK 321 281 L
Component: V553 MTFP 003 0576
Serial number: 75145041170327001331
All those gearbox error codes and the black gear oil points to the gearbox portion of the transmission. I remember a TSB about that gearbox oil pump, its electric. Was the mechatronics fluid overfilled in the past during the required fluid change? If so the mechatronics fluid will overflow into the gearbox portion and contaminate the special gear oil. Good luck with the repair, maybe take some pictures?
.
Audi service manuals are a bit of a nightmare to figure out because they cover multiple A4 variants and don't make it easy to figure out what is what. As far as I can figure out from my service manuals the 0CJ has a dual mass flywheel. The service manual has a notation that clicking from the LuK dual mass flywheel that occurs with every 90 deg of rotation is normal as you turn the flywheel. You might want to review the service manual to make sure that your flywheel noise is something other than the normal clicking. That said, it is not obvious how a flywheel problem could cause your problems.
It is a bit of a hale Mary move; but, I would have been inclined to do a mechatronics flush and adaptation first to see if it made the problem go away, just because it is so much easier than dropping the transmission. But, I suspect that is likely not the problem.
Since you are having first and third gear problems, the service manual indicates that it is a common rail/ shift fork for 1st and 3rd so the fork might be damaged. There is also a thing called the gear actuator or gear positioner module that as far as I can figure out operates the four shifter forks. That module might be bunged and failing to operate the 1st / 3rd shift fork. According to the DTC listing P2849 means shift fork "A" stuck. P284D is "Shift Fork A unrequested movement". I eventually gave up looking for "shift Fork A" because I could not find anything in the transmission section of the service manuals which said which fork is "A"; however, the DTC section of the SM does have a confusing reference to gear actuator 1-3 for DTC 2849. Since the transmission is out, I might start with checking the gear actuator mechanism and then the shift fork. Unfortunately, I did not see anything that tells you how to diagnose the gear actuator mechanism.
Hello hello,
Finally got around to fully dissasemble the whole gearbox. The mechatronics is clean and working properly. The party started when I removed the housing off the gears. Let's take a trip throughout my day.
1. After removing the plastic cover that has a circlip, first thing I saw was that the shaft has signs of being heated/burned. Good start.
2. After batlling with the shaft, some hammering I finally removed it, since the shaft got hot and "welded" itself onto the seal.
3. During the removal the start of the gears seemed fine, all good, let's continue. In the middle I saw some trash, meh, could be worse. Once the housing got fully removed, the party started.
4. There were some broken off parts of the gears themselves. Few gears in the back were "loose". There was a sign of heat/not enough oil. Basically the whole gears unit is done.
My theory is that the oil pump got clogged and thus not enough oil went on to the "back" gears. Doubt it's that, but that's my theory. Everyone is free to give their thougts.
Since some parts of the gears broke off and gears became loose and I'm guessing that's the root of the shift forks, gear selector errors not being to properly engage. If anyone is interested I can take more pictures and give more info on the state of the gearbox, electrical parts, pump and ect.
Thank you for the pictures!
Does the gear oil pump have a screen on the intake to collect the debris?
I wonder if changing the gear oil and cleaning the pump could prevent this type of failure?
.
Thank you for the pictures!
Does the gear oil pump have a screen on the intake to collect the debris?
I wonder if changing the gear oil and cleaning the pump could prevent this type of failure?
.
By screen you mean a filter? Then yes, but it full of crap. And question to second. Personally, I think yes, since the gears did not get proper amount of lubrication ant overheated. Well, **** happens. Atleast I'm doing everything myself and saving a ton of money.
By screen you mean a filter? Then yes, but it full of crap. And question to second. Personally, I think yes, since the gears did not get proper amount of lubrication ant overheated. Well, **** happens. Atleast I'm doing everything myself and saving a ton of money.
I give you credit for disassembling this complex transmission. Are you planning to replace the damaged components or get a donor transmission from a recycling yard? If you are planning to replace parts, do you know if Audi makes the internal parts available in their parts catalog?
I give you credit for disassembling this complex transmission. Are you planning to replace the damaged components or get a donor transmission from a recycling yard? If you are planning to replace parts, do you know if Audi makes the internal parts available in their parts catalog?
Still thinking what to do. Some parts aren't really off the shelf, but if you call them, you might talk them into it because I've gotten weirder, more specific parts from them even though they were not really for "sale".
Changing just a few gears is not an option, because the whole gear unit has overheated and welded itself and won't come off easy, will need lots of heating, hammering and will damage few more gears, bearings and ect.
Buying new gear unit is overpriced as hell, it would be around 3000€ or more, used ones are around 700-1000€. But after buying a used one I'd need to change many seals, bearings because when removing the faulty one I had to use a lot of force to remove and damaged a few parts in progress. Those parts are reasonably priced 20€-80€, but would spend upto 400€ on those and changing a used gear unit would come out at 1000€-1400€ plus MTF, ATF oils and ATF filters, ATF is quite expensive, it's like 40€-50€/liter and I think I'd need like 7 liters.
My best option I think will be to buy a used transmission which is like 750€-1300€, on the cheaper side if I manage to find one without flywheel, front wheel driveshaft, transfer box case and module and ect. Because those are working on my current one. Change oils and filters. Keep my old clutch, mechatronics unit, oil pump in my garage incase something breaks again and I have spare parts if needed. Or I could seel my current transmissiom for parts, used clutch is like 300€ (has only 15k km on it), mechatronics unit around 500€, oil pump 100€ and then there's a few useful ones that people do buy. But keeping spare parts sounds like a plan aswell.
08-18-2023, 08:36 AM
DSG problems, gears either stucks on 2nd or 4th.
