[Marktee]

I replaced the transmission fluid a month ago where I was told the jerking of car was caused by the wrong fluid. Yesterday I was changing the fluid with Pentosin fluid and discovered while draining the fluid the murky color water. I tried to drain it all but not all and injected the blue color fluid into the transmission and started the car as I was supposed to do and lots of MURKY fluid came out.
I searched it on the forum and radiator cooler has failed. Is the transmission cooler outside or inside the radiator in 2012 c250 turbo 1.8? The expansion tank is full iin green coolant despite the light comes on as check coolant level

 

[friendlyMBtech]

The transmission cooler is part of the radiator. The transmission fluid lines go through the side tank of the radiator. The coolant is leaking into the transmission fluid this way. You need a radiator and probably a transmission due to the coolant contamination.