6MT to DCT swap

[Starboy]

Originally Posted by tsk94

The DCT overheating issues are easily addressed with upgraded cooler and/or larger DCT pan. Lots of info on it in the track sub-forum, many hardcore (and fast) guys tracking & racing DCT's.

Looks like overheating is more of a side effect than the main problem in this case, and people who had the same problem usually end up replacing the entire transmission (replace the oil pan/mechatronics/oil cooler didn't solve the problem)

To quote from another user from the forum:
"In retrospect since the higher and more aggressive shift modes trigger the code, perhaps the clutches are slipping and or the synchromesh are worn, or the selector fork servo is worn."

https://www.m3post.com/forums/showth...1957220&page=2

[Starboy]

Originally Posted by Helmsman

Also various threads on over heating that isn't necessary due to...over heating. If you haven't already I'd check the basics i.e. fluid/filters, read the built in temps sensors to see that they actually align when over heating. If one sensor is going bad it will generate a code/limp mode as if fluid is over heated.
Far from an expert here but believe the car will go in limp mode first if due to over heated rather than start missing gears..?

in my case, just a little bit of aggressive driving (rev over 4k or 5k RPM) would trigger the transmission to lose gear (randomly on 1/3/5, sometimes 4/6), while the transmission temp was perfectly ok

Took me a while to figure out there could something wrong with the valve body, quote from this post:

bmw mechatrnoic:

If you read the codes, you may get fault codes related to the valve body also known as the BMW mechatronic. BMW ZF mechatronic are notorious for problems with 2 to 1 st gear downshift or shift flare during the upshift. These harsh upshifts and downshifts are often due to a TTC clutch failure, overheating, damaged solenoid, worn selenoid springs and other problems with the mechatronic unit.
If you checked everything above but are still having problems with your BMW transmission the cause most likely is the mechatronic unit. If you are looking to save money, you can consider replacing only the solenoids in the mechatronics unit/valve body.

https://www.youcanic.com/bmw-transmission-problems/

[Helmsman]

Originally Posted by Starboy

in my case, just a little bit of aggressive driving (rev over 4k or 5k RPM) would trigger the transmission to lose gear (randomly on 1/3/5, sometimes 4/6), while the transmission temp was perfectly ok

Took me a while to figure out there could something wrong with the valve body, quote from this post:

bmw mechatrnoic:

If you read the codes, you may get fault codes related to the valve body also known as the BMW mechatronic. BMW ZF mechatronic are notorious for problems with 2 to 1 st gear downshift or shift flare during the upshift. These harsh upshifts and downshifts are often due to a TTC clutch failure, overheating, damaged solenoid, worn selenoid springs and other problems with the mechatronic unit.
If you checked everything above but are still having problems with your BMW transmission the cause most likely is the mechatronic unit. If you are looking to save money, you can consider replacing only the solenoids in the mechatronics unit/valve body.

https://www.youcanic.com/bmw-transmission-problems/

The DCT certainly doesn't over heat from a bit of aggressive driving, according to specs designed to handle 9k rpm. I'd say something else is the root cause in your case, no idea what though.