My MDCT saga continues (new issues after service)

[Andryuha]

To summarize, my issues started after I had a pan/filter service performed. After said service, I started having multiple issues that nobody seems to be able to diagnose (clunky shifting mainly). Last shop told me that I need a new transmission, but we ended up doing another flush and replaced a leaky mechatronics sleeve o-ring. I should also mention that the original shop put Liqui Moly fluid in. I ran the car with this fluid for roughly 2k miles before having it flushed again with Pentosin.

Current symptoms: The car drives fine when driving normally. Although I do get a faint whining/whirring noise from the gearbox. When I try driving aggressively, I run into problems that occur seemingly at random. At times, the car bogs down when switching from first to 2nd gears. One time it skipped 3rd and fourth and went straight to 5th gear. No problems with downshifts. The transmission does not overheat and there are no error codes. What the heck could be the problem? How would you go about addressing the issue? I already visited all of the reputable shops in my area and they all made different conclusions.

I am thinking that this could be software - related because it's all very random and sporadic. Currently, the car has Dinan DCT tune.

[Theodore]

You should switch back to the stock DCT tune (7847869) and see what happens. You may like it and your 0-60 time should improve:

M3 0-60 Times

[Andryuha]

Originally Posted by Theodore

You should switch back to the stock DCT tune (7847869) and see what happens. You may like it and your 0-60 time should improve:

M3 0-60 Times

Hmm, I'll have to give that a try. From that thread, it looks like the sudden power loss at 1-2 switch might be due to fuel cut off. It only happens in manual mode.

[Helmsman]

OP, you noticed the BMW doc about the need to use Pentosin? What did the shop say after filling incorrectly?

[Andryuha]

Originally Posted by Helmsman

OP, you noticed the BMW doc about the need to use Pentosin? What did the shop say after filling incorrectly?

They said that LiquiMoly is just as good, so I let it go (didn't know any better at the time). I ended up going back to the original shop after I discovered a mechatronics sleeve leak. However, after they tried to convince me that the mech unit uses a completely different fluid than the actual transmission, my heart sank and I realized that they have no clue WTF they are talking about. That's when I went to a different shop to get the work done (had them flush the system with the correct fluid at that time).

[amrazM]

did you reset the adaptations of the trans? theres 3 procedures with ista and the measures have to be completed in order.

[Helmsman]

Originally Posted by amrazM

did you reset the adaptations of the trans? theres 3 procedures with ista and the measures have to be completed in order.

This is interesting, not running ISTA myself though. Trying to make the dealer to explain what they actually have performed during their fail investigation of my box, and as it seems (quite) often one have to remind/hint what they should do... Would you say mentioned reset a pretty straight forward procedure? (don't think they've dode that or taken any temp measurements)

Thanks

[Helmsman]

Originally Posted by Andryuha

They said that LiquiMoly is just as good, so I let it go (didn't know any better at the time). I ended up going back to the original shop after I discovered a mechatronics sleeve leak. However, after they tried to convince me that the mech unit uses a completely different fluid than the actual transmission, my heart sank and I realized that they have no clue WTF they are talking about. That's when I went to a different shop to get the work done (had them flush the system with the correct fluid at that time).

The fact that the issues started after they've used a non specified fluid would make me worried.

[amrazM]

Originally Posted by Helmsman

This is interesting, not running ISTA myself though. Trying to make the dealer to explain what they actually have performed during their fail investigation of my box, and as it seems (quite) often one have to remind/hint what they should do... Would you say mentioned reset a pretty straight forward procedure? (don't think they've dode that or taken any temp measurements)

Thanks

Its necessary to do the reset on the transmission operation data as its what the mechatronic uses to operate. The clutch reset measures the operating clutch line pressure for basket 1 and 2 each of which come back with individual values. there is also the torque curve characteristic for pv1 and pv2 and the actual transmission adaptation itself. usually after people change the fluid you get more and more complaints of knocking going into gear and from 2-1 because nobody relearns in the gearbox after completely this as the procedure itself takes about 15 minutes plus the time to bring the gearbox up to temp.


additionally about your comment, historically LM makes everything louder so the whine you are hearing is likely from the transmission oil pump which should go away after some usuage with fluid other than LM. Not to bash but i have no idea why people would use LM in the gearbox instead of a proven DKG fluid like Pentosin or Motul multi DCT. Personally I run Amsoil in my transmission without any sort of complaint.

[rcracin]

Aside from the adaptations reset, could it be that the fill procedure wasn't properly done? It's been a few years but I remember having the car on 4 jackstands and having to rev and hold at different intervals with ista running. I believe deansbimmer has a detailed post on the fill procedure.

[Helmsman]

Originally Posted by amrazM

Its necessary to do the reset on the transmission operation data as its what the mechatronic uses to operate. The clutch reset measures the operating clutch line pressure for basket 1 and 2 each of which come back with individual values. there is also the torque curve characteristic for pv1 and pv2 and the actual transmission adaptation itself. usually after people change the fluid you get more and more complaints of knocking going into gear and from 2-1 because nobody relearns in the gearbox after completely this as the procedure itself takes about 15 minutes plus the time to bring the gearbox up to temp.

I had an indy to change fluid, Tstat and sump/gasket (initiated on the heat error code). I don't believe they reset the adaptation - Do you mean that this should be performed after fluid change?

After this I was sent to the main dealer (in Sweden). As they found nothing wrong, I'm trying to make them explain what they in fact did.

Thanks

[amrazM]

Originally Posted by Helmsman

I had an indy to change fluid, Tstat and sump/gasket (initiated on the heat error code). I don't believe they reset the adaptation - Do you mean that this should be performed after fluid change?

After this I was sent to the main dealer (in Sweden). As they found nothing wrong, I'm trying to make them explain what they in fact did.

Thanks

Yeah you need to do this afterwards. Theres other things at play here, the mdct gearbox is a bit challenging to fill properly as it needs to be at a certain temp and you should rev the car as the fluid pump is driven off the input shaft so its output is dependent on engine speed rpms. you need to verify the fill level which is most critical. I do remember the heat issues you had before but many people drive these cars with a bad mechatronics as components such as the internal gearbox temp sensor is not servicable but its also a fault that the car can live with if its intermittent.

course of action is verify fluid level followed by ista procedures.

[Helmsman]

Originally Posted by amrazM

Yeah you need to do this afterwards. Theres other things at play here, the mdct gearbox is a bit challenging to fill properly as it needs to be at a certain temp and you should rev the car as the fluid pump is driven off the input shaft so its output is dependent on engine speed rpms. you need to verify the fill level which is most critical. I do remember the heat issues you had before but many people drive these cars with a bad mechatronics as components such as the internal gearbox temp sensor is not servicable but its also a fault that the car can live with if its intermittent.

course of action is verify fluid level followed by ista procedures.

Thanks again mate. I simply have to assume the dealer verified fluid level after the change by the indy, and had the heat code prior the change as well. Something happens at stand still/stop and go traffic, clutches appear completely off, but this is typically when the heat code comes up. Ah well, will keep dealer foe more details.

[Andryuha]

Originally Posted by amrazM

Yeah you need to do this afterwards. Theres other things at play here, the mdct gearbox is a bit challenging to fill properly as it needs to be at a certain temp and you should rev the car as the fluid pump is driven off the input shaft so its output is dependent on engine speed rpms. you need to verify the fill level which is most critical. I do remember the heat issues you had before but many people drive these cars with a bad mechatronics as components such as the internal gearbox temp sensor is not servicable but its also a fault that the car can live with if its intermittent.

course of action is verify fluid level followed by ista procedures.

Thank you so much for explaining all of this! Sounds like there's a chance that I can still rectify my issues, since I haven't driven the car much after the service. It would also make sense why it's still whining after the most recent flush, since I have driven maybe 200 miles since then. How do I verify the fluid level? Is it done with a computer? I do have INPA for my Z3M and it looks like I can use the same cable to run ISTA as well. I should be able to DIY the re-learn procedure.

It's just mind boggling that all 3 "specialists" that I went to pretended like everything is fine and running properly.

[amrazM]

Originally Posted by Helmsman

Thanks again mate. I simply have to assume the dealer verified fluid level after the change by the indy, and had the heat code prior the change as well. Something happens at stand still/stop and go traffic, clutches appear completely off, but this is typically when the heat code comes up. Ah well, will keep dealer foe more details.

I highly doubt it, if you open the plug with the car cold fluid will poor out and to the untrained bmw technician which they all are one will assume its filled. Coming from someone from the dealer, techs today do not go the extra mile. the reason why you wait to fill the trans to full capacity is because of the fluid circuit which remains closed when the trans warming up thus you will be left with a false sense of the gearbox being correctly filled.

[amrazM]

Originally Posted by Andryuha

Thank you so much for explaining all of this! Sounds like there's a chance that I can still rectify my issues, since I haven't driven the car much after the service. It would also make sense why it's still whining after the most recent flush, since I have driven maybe 200 miles since then. How do I verify the fluid level? Is it done with a computer? I do have INPA for my Z3M and it looks like I can use the same cable to run ISTA as well. I should be able to DIY the re-learn procedure.

It's just mind boggling that all 3 "specialists" that I went to pretended like everything is fine and running properly.

The car may run fine when cold but most issues with this gearbox become prominent at operating temp.

you have to use ista with the kcan cable. I will be performing this process later in the week, ill make a detailed video.

[Andryuha]

Originally Posted by amrazM

The car may run fine when cold but most issues with this gearbox become prominent at operating temp.

you have to use ista with the kcan cable. I will be performing this process later in the week, ill make a detailed video.

In my case, it has actually been the opposite - the shifting is a lot smoother at operating temps. I did another experiment today - I switched the power button off and with the exception of the whine, the car ran flawlessly (but obviously a bit less responsive).

I do have the kcan cable and a video would be awesome. Do you have a YT channel by chance?

[amrazM]

Originally Posted by Andryuha

In my case, it has actually been the opposite - the shifting is a lot smoother at operating temps. I did another experiment today - I switched the power button off and with the exception of the whine, the car ran flawlessly (but obviously a bit less responsive).

I do have the kcan cable and a video would be awesome. Do you have a YT channel by chance?

i do.

https://www.youtube.com/channel/UCWN...Tgth-g9Fw5K2-g

[Andryuha]

Originally Posted by amrazM

i do.

https://www.youtube.com/channel/UCWN...Tgth-g9Fw5K2-g

Subbed and thanks again!

[Andryuha]

I managed to get my hands on a copy of ISTA and there are 6 transmission codes. There is also a whole procedure (as amraz suggested). My plan is to properly check the DCT oil level, top it off if necessary and run through the necessary ISTA procedures. I am almost 100% certain that none of the shops I took it to followed this procedure.

[Helmsman]

Originally Posted by Andryuha

I managed to get my hands on a copy of ISTA and there are 6 transmission codes. There is also a whole procedure (as amraz suggested). My plan is to properly check the DCT oil level, top it off if necessary and run through the necessary ISTA procedures. I am almost 100% certain that none of the shops I took it to followed this procedure.

Interesting, looking forward to your update!

[Andryuha]

Originally Posted by Helmsman

Interesting, looking forward to your update!

Had some time to work on the car this morning and I'm happy to report that my issues have been pretty much resolved! ISTA makes it really simple to run through diagnostics and adaptations - there are literally step by step instructions that a child can follow. There were no faults found after I deleted the codes and ran the tests, but I found it neat that there was a warning related to "perceived gear selection comfort" or something along those lines. I basically completed all of the tests, checked the oil level (there are specific instructions on how to do this) and reset the adaptations. Checking the oil was probably the hardest part of the process (and it wasn't hard at all)

The gear selection is smooth as butter and there are no delays - exactly how it should be. I've also noticed that the clunk when switching from P is almost completely gone now. I can still hear a bit of a whine, but it is definitely a lot less noticeable.

Huge kudos to amrazM!