[Dr777]

Hey guys I seem to be having a problem with my transmission
I own a 08 335i with around 156k. The engine was replaced around 153k by me and the transmission is still the same one as far as I know.
I noticed when I do hard acceleration from 1st gear my car will shake violently and the rpms will jump almost like you lost traction it will shift in time in 1st gear but once it gets to 2nd gear it will over rev to about 7.5k.

The only error I got was 4f70
I should also mention sometimes though rarely I will get 4f85 under WOT in 3rd gear it's only happend twice

The only service I've done to the transmission is a fluid change and a transmission pan change (cracked the pan)

The transmission ecu is stock but the engine has a stage 1+ MHD flash with vrsf inlets and burger motorsports DCI

I've read other threads that slippage can sometimes be solved by a rebuilding the valve body. I picked one up at a local salvage yard for about 60-70 bucks with all the solenoids and even the seals. (If that doesn't work I'll just sell it and hope to gain a profit)

My question is what else could it be that is causing this issues

[relative4]

Step 1 is replace the double-square seal and tube seals between the valve body and the transmission.

[Dr777]

Originally Posted by relative4

Step 1 is replace the double-square seal and tube seals between the valve body and the transmission.

I replaced the bridge seal the o-rings fell out as I took it out. Now admittedly I did not have a brand new bridge seal on hand so I used the one I pulled from the other transmission it didnt look took bad almost like it was recently replaced. Transmission is still acting up I reset adaptations and it got worse I would get a flare in rpms going from 2nd to 3rd and 3rd to 4th
I got the following codes now and engine code

2c7e in the dme
4f92 and 4f89 in the transmission
And on top of that the valve body I picked up was different then the one in my transmission I apparently have the 6hp21. I thought all rwd e9x came with the 6hp19 transmission