E92 M3 DCT acting strange

[Karimnassef08]

Hey guys, I have a 08 m3 with 90k miles equipped with the dct. Recently my old transmission went bad, and I had swapped it for a 43k mile transmission that came out of a 2009 car. After swapping the transmission, im not satisfied, the shop that worked on my car and did the swap say everything is normal but I don't agree, and Id like a second opinion.

Some issues I've noticed:
-On cold starts the car jerks really badly for the first 15 seconds in D/S or reverse, its like the clutch wants to engage but keeps slipping. And then it smoothes out afterwards.
-The car is not smooth, I understand it has quirks as its a dual clutch mimicking a torque converter, but it feels like SMG in traffic, which it should not!
-Sometimes when I beat on the car, for example, if I want to drift, or dump the clutch, the car cuts power, shifts a gear up on its own (in manual mode) and then gradually allows full power to come back up. Its very annoying, its not like I'm bouncing off the rev limiter, and even if I am, the M-DCT shouldn't upshift for me in manual mode.
-Ive put about 5K miles since the swap, and my car has went into transmission malfunction mode (with only even gears available) twice
-When I come to a complete stop, on even pavement, my car just starts to roll back? it shouldn't roll back.
-When I get off throttle, my car holds the throttle, its not accelerating, but its like cruise control is set, and it holds its speed for 2 or 3 seconds, and then starts decelerating.
-The shop that did the swap said my clutch pack clamping force is 100% and they reset the transmission adaptations and that everything in my car is normal, but I refuse to accept it because my old transmission never had these issues.

And I bought the new transmission from a very reputable shop, so I know the transmission isn't defective, so could the issue be due to me needing the clutches reset, or maybe the transmission was installed incorrectly?

If anyone could please help me out, I would highly appreciate it!

[amrazM]

Did you replace the mechatronic unit?

[bmwfst1]

These transmissions do weird things when low on fluid. Check fluid level first.

[Karimnassef08]

Originally Posted by amrazM

Did you replace the mechatronic unit?

If I am not mistaken, im pretty sure he used the mechatronic unit that came with the new transmission. He did take off the unit cover to replace the side gasket, do you think he might've damaged it?

Update:
- I spoke with the shop, and he confirmed that he did not use the old (original mechatronic unit) he used the one that came with the new transmission.

[Karimnassef08]

Originally Posted by bmwfst1

These transmissions do weird things when low on fluid. Check fluid level first.

Fluid is filled to proper capacity, and was filled with the correct procedure. He did use Motul DCT-fluid instead of the pentosin fluid. But many people with M dct and even the 135s that have DCT have used this transmission fluid, so I don't see it as being an issue.

[Karimnassef08]

Oh, I should also add that sometimes in auto mode, when I give it a 45% or so throttle, the car only downshifts 1 gear, when it should downshift at least 2 or 3 gears.

Another issue I noticed is that if Im going 40 mph (30-50ish), let off the throttle, and get back on after a few seconds, the car jerks (doesn't shift gears, just jerks as if its reengaging the clutch) is this normal?

[wfdeacon88]

Originally Posted by Karimnassef08

Oh, I should also add that sometimes in auto mode, when I give it a 45% or so throttle, the car only downshifts 1 gear, when it should downshift at least 2 or 3 gears.

Another issue I noticed is that if Im going 4 mph, let off the throttle, and get back on after a few seconds, the car jerks (doesn't shift gears, just jerks as if its reengaging the clutch) is this normal?

I don't think many people apply that much throttle in auto that often, but it's definitely not the smoothest doing any spirited driving auto.

As the for 4 mph thing... I believe that's pretty normal for mine. Very slow speed on and off throttle isn't smooth at all unless it's very slow easing off and on the throttle. When my AC is on, slow speeds is definitely worse I assume due to belt

[Karimnassef08]

Originally Posted by wfdeacon88

I don't think many people apply that much throttle in auto that often, but it's definitely not the smoothest doing any spirited driving auto.

As the for 4 mph thing... I believe that's pretty normal for mine. Very slow speed on and off throttle isn't smooth at all unless it's very slow easing off and on the throttle. When my AC is on, slow speeds is definitely worse I assume due to belt

My bad bro, I meant to say 40! I know the transmission is quirky at slow speeds, but mine seems abnormally clunky.

[tmak90]

I’ve dealt with a similar issue where I would get a transmission malfunction, my even gears clutch wouldn’t work and got a clutch pressure too low code. Had my car looked at by Coulter (Deansbimmer) and he saw no leakage and determined it could have been an internal leak or failing sensor in the high pressure circuits inside the transmission. May need to try resetting adaptations again but I ended up just replacing a newer transmission rather than diagnosing the issue further which could have costed more.

[Karimnassef08]

Originally Posted by tmak90

I’ve dealt with a similar issue where I would get a transmission malfunction, my even gears clutch wouldn’t work and got a clutch pressure too low code. Had my car looked at by Coulter (Deansbimmer) and he saw no leakage and determined it could have been an internal leak or failing sensor in the high pressure circuits inside the transmission. May need to try resetting adaptations again but I ended up just replacing a newer transmission rather than diagnosing the issue further which could have costed more.

I purchased a low milage transmission from a very reputable shop, and the transmission I bought hadn't been sitting on the shelves for more than 4 months, I doubt the transmission is bad. I believe it is something wrong with the software end, the hardware is tried and tested.

[tmak90]

Need to check for codes with scanner like ISTA

[Karimnassef08]

Originally Posted by tmak90

Need to check for codes with scanner like ISTA

Will do, I will go over to my friends house this weekend, retrieve the codes, and update you.

[scrammer]

OP, I am certainly not an expert on software programming, and it looks like you have taken the right steps, so why not drop $135 on a reputable company like Dinan for a DCT flash and see if that takes care of your gremlins?

... From their website

The Dinan Performance DCT software enhances the driving experience of M3s with DCT transmissions with quicker and smoother upshifts/downshifts.

CLICK TO VIEW APPLIED MODELS ▲
This item is worth 1 point(s) towards your Dinan Badge.
PRICE: $134.44
TO ORDER CALL DINAN AT 1-800-341-5480

[shy222]

Google Alex Dct coding and update your dct transmission program.

[amrazM]

I’m gonna be honest here, if your Dct is locking on one gearset there’s a problem inside that software won’t fix.

[Karimnassef08]

Originally Posted by scrammer

OP, I am certainly not an expert on software programming, and it looks like you have taken the right steps, so why not drop $135 on a reputable company like Dinan for a DCT flash and see if that takes care of your gremlins?

... From their website

The Dinan Performance DCT software enhances the driving experience of M3s with DCT transmissions with quicker and smoother upshifts/downshifts.

CLICK TO VIEW APPLIED MODELS ▲
This item is worth 1 point(s) towards your Dinan Badge.
PRICE: $134.44
TO ORDER CALL DINAN AT 1-800-341-5480

I was actually looking to get the GTS software from Alex, but I wanted to take care of maintenance items, and my transmission issues before I spend any on mods!

[Karimnassef08]

Originally Posted by amrazM

I’m gonna be honest here, if your Dct is locking on one gearset there’s a problem inside that software won’t fix.

I don't think thats the case. A buddy of mine spun a rod on his s65, so when he swapped the engine, his old transmission (that never had issues) started going into trans malfunction mode, I believe thats partially due to install, but also software, he's still figuring out his issues. So we both haven't come to a conclusion, but I wouldn't say that the transmission is failing. It shifts hard, doesn't slip, and handles the abuse for the most part, its just at the most random times that it'll upshift for me. And its only locked me out of a specific gear set twice in the past 5k miles. One time was when I braked really hard, and another time when I punched it in auto mode.

[sdbmwcoding]

Originally Posted by Karimnassef08

I don't think thats the case. A buddy of mine spun a rod on his s65, so when he swapped the engine, his old transmission (that never had issues) started going into trans malfunction mode, I believe thats partially due to install, but also software, he's still figuring out his issues. So we both haven't come to a conclusion, but I wouldn't say that the transmission is failing. It shifts hard, doesn't slip, and handles the abuse for the most part, its just at the most random times that it'll upshift for me. And its only locked me out of a specific gear set twice in the past 5k miles. One time was when I braked really hard, and another time when I punched it in auto mode.

The software won't cause these issues, what can cause them are the adaptations of the actual transmission. If the shop reset adaptations they might've done a slight reset. You need to perform a full dct adaptation reset via ISTA. That'll smooth everything out. The gts flash does smooth things out but it's really not as crazy of a change as people say it is. Doesn't fix all the dct quirks with just a software change