BMW ECU Transmission

[rottie7]

Hi, Got the Trans. Malfunction error and it wouldn't let me shift gears to move until I bypassed the message. I had been smelling a little burnt smell, but it went away quickly and only happened 2 times.

Do I need to flush my transmission or just have them refill it? What do you suggest, I have read to never flush it... So I am concerned about causing damage.

Thank you

[Redd]

Flush. Your. Transmission. Fluid. Also change your filters while you're in there. BMW tells you not to so that they can sell you more gearboxes. I would wager that you're probably low on fluid.

[scubajim]

I think the concern was doing a power flush of the transmission fluid. A normal drain and replacing the pan with the filter attached is fine. If you are DIY need to look at the specific process which requires you to get the car up to the specific temperature before top off.

[Ralph III]

Hello OP,
In regards to servicing the transmission you'll need to temporarily remove the mechatronics unit and then install all new seals/sleeves, as well as fluid and pan. ZF recommends servicing the transmission as such, every 50k miles or so. Since you are having issues, I'd advise replacing the solenoids also. It's a little time consuming but it's a project that most any DIY can perform. As Scuba noted, the transmission temperature has to be at a specific temperature for final top-off of the fluid. Afterward, you'll need to reset the adaptations via BMW software. It will take the vehicle about 350 miles to re-learn the shifting process, so do not drive it aggressively during this period. Just drive it casually in order to limit any hard shifts.

Good luck,
Ralph

[Raimo5]

If the burnt smell is coming from transmission and you are having malfunction then odds are that fluid change is not going to cut it for you. Your transmission is toast and needs to be rebuilt or replaced.