DCT Replacement Compatibility

[chaos888]

The DCT on my '09 is likely dead and I'm looking for a used one to replace it with.

I'm just starting to learn about the whole process. Are all e90/e92 DCTs okay to use or do I need to look for specific part numbers for compatibility.

Do I use the mechatronic from my existing DCT on the new unit? Or is there a way to code the new mechatronic to my car?

Thanks!

[GORDON.M3]

Originally Posted by chaos888

The DCT on my '09 is likely dead and I'm looking for a used one to replace it with.

I'm just starting to learn about the whole process. Are all e90/e92 DCTs okay to use or do I need to look for specific part numbers for compatibility.

Do I use the mechatronic from my existing DCT on the new unit? Or is there a way to code the new mechatronic to my car?

Thanks!

What happened to the DCT?

[chaos888]

Just a mundane drive to go get groceries, a couple blocks from home, started off and upshifted to 2nd and the screen lights up with a transmission malfunction (I wasn't able to read the rest of it and I wasn't able to find it in the menus later). It goes into 3rd where it stays.

At the next light, stuck in 3rd, I tried to pull away and the car was crawling so the best thing I could do was pull in to the center median. I thought maybe if I shut it down and restarted it would reset but instead it would just rev. Wouldn't go into gear, couldn't even put it in N to push it, just went back to P.

Towed it to my mechanic who took off the pan and found nothing wrong with any of the immediately accessible parts - sucking jet pump, filters, etc., no debris or bits.

Next step, not done yet, take out the transmission to see if it's the pump inside. The worry was when it failed it may have messed up the input shaft.

My thought was, either way the transmission has to come out and we can see if there's anything wrong but we wouldn't really know until we replace/repair and reinstall the transmission only to find there's still an issue which would be a waste of money. Plus I'd have a DCT with fewer miles replacing it.

From what I heard, all the DCT's ('08-13) are the same and I feel like any DCT from then should work but just wanted to make sure I'm not missing something.

[GORDON.M3]

Originally Posted by chaos888

Just a mundane drive to go get groceries, a couple blocks from home, started off and upshifted to 2nd and the screen lights up with a transmission malfunction (I wasn't able to read the rest of it and I wasn't able to find it in the menus later). It goes into 3rd where it stays.

At the next light, stuck in 3rd, I tried to pull away and the car was crawling so the best thing I could do was pull in to the center median. I thought maybe if I shut it down and restarted it would reset but instead it would just rev. Wouldn't go into gear, couldn't even put it in N to push it, just went back to P.

Towed it to my mechanic who took off the pan and found nothing wrong with any of the immediately accessible parts - sucking jet pump, filters, etc., no debris or bits.

Next step, not done yet, take out the transmission to see if it's the pump inside. The worry was when it failed it may have messed up the input shaft.

My thought was, either way the transmission has to come out and we can see if there's anything wrong but we wouldn't really know until we replace/repair and reinstall the transmission only to find there's still an issue which would be a waste of money. Plus I'd have a DCT with fewer miles replacing it.

From what I heard, all the DCT's ('08-13) are the same and I feel like any DCT from then should work but just wanted to make sure I'm not missing something.

Sorry to hear... its quite rare that a DCT would fail completely.
Newer facelifted DCTS will have to have the ISN rewritten to match your car. without doing that the car will not accept the DCT and the dct will not start.

[chaos888]

My understanding of this swap is still vague. What is "ISN"?

I was under the impression that by swapping in my mechatronics unit (or the controllers/electronics) into the new DCT, I could avoid that reprogramming issue. Not sure what all the steps are.

[Theodore]

Originally Posted by chaos888

Just a mundane drive to go get groceries, a couple blocks from home, started off and upshifted to 2nd and the screen lights up with a transmission malfunction (I wasn't able to read the rest of it and I wasn't able to find it in the menus later). It goes into 3rd where it stays.

At the next light, stuck in 3rd, I tried to pull away and the car was crawling so the best thing I could do was pull in to the center median. I thought maybe if I shut it down and restarted it would reset but instead it would just rev. Wouldn't go into gear, couldn't even put it in N to push it, just went back to P.

Towed it to my mechanic who took off the pan and found nothing wrong with any of the immediately accessible parts - sucking jet pump, filters, etc., no debris or bits.

Next step, not done yet, take out the transmission to see if it's the pump inside. The worry was when it failed it may have messed up the input shaft.

My thought was, either way the transmission has to come out and we can see if there's anything wrong but we wouldn't really know until we replace/repair and reinstall the transmission only to find there's still an issue which would be a waste of money. Plus I'd have a DCT with fewer miles replacing it.

From what I heard, all the DCT's ('08-13) are the same and I feel like any DCT from then should work but just wanted to make sure I'm not missing something.

I would first check the rear wheel speed sensors (and the rear wheel bearings which have a magnet to interact with the wheel speed sensors). Check out this thread. In my personal experience when my rear wheel speed sensor failed, my DCT acted erratically and would not shift into any gear higher than 3rd.

[chaos888]

Thanks! I guess that's worth a shot but I don't think I got any error codes related to wheel sensors.