DCT Transmission Leaking

[Gregrobin]

The shop that did the PPI on the M3 I am purchasing noted the transmission is leaking, and took a pic. From my research this could be seals, amongst other things. Is there any way to diagnosis this without taking it apart? What's my worst case scenario?

[greyspoke]

Take a look at this post from Coulter, absolute expert in our cars.

[spammysammich]

Originally Posted by Gregrobin

The shop that did the PPI on the M3 I am purchasing noted the transmission is leaking, and took a pic. From my research this could be seals, amongst other things. Is there any way to diagnosis this without taking it apart? What's my worst case scenario?

Without at least removing the transmission cover/shroud? No. Good luck trying to find one that isn't at least seeping. The person doing the PPI could use a borescope to chase the leak a little but there are so many places to leak from a quick look like what you posted isn't gonna tell you jack. The most important thing is appropriate fluid level/condition when slightly warmed up, then determining active leak (leaving puddles or drops) vs seepage that just leaves the pan moist.

[omgzirra_exe]

worse case scenario is a new DCT

best case scenario is a FULL DCT service = fluid + hardware + internals, there's a unit inside the trans that tends to break due to being plastic.. but that usually is the fluid pick up unit.

[Gregrobin]

Thanks

[Redd]

The plastic DCT pan is prone to leaks. This is very common. If you got no dct errors I wouldn't worry about it, but be prepared to spend some money for a full dct service.

[drwankel]

There are 3 places where the transmission can leak. The bottom pan, the mechatronics cover on the side of the transmission, and the wire harness oring on the top of the transmission.

Due to the amount of leakage, you'll want to have the transmission serviced anyway, which requires replacing the bottom pan. While there, you'll want to ensure the leak isn't coming from one of the other two places, or just proactively address them.

[spammysammich]

Technically 6 places; the pressure filter o-ring can go flat, and there have been leaks reported from the lines going to the heat exchanger from the thermostat. My lucky ass even had a leak between the thermostat and the transmission case. It just loves to share pentosin with the rest of the world.