[mdputnam]

I currently have a 135is with ZF's 7 speed double clutch transmission. I got a 2016 M235i loaner to drive over the weekend while my car was in for service. It had the standard ZF 8 speed automatic. I was impressed by the smoothness of the 8 speed compared to the 7 speed double clutch, but was somewhat dismayed by its inability to slow the car after the rpms rose above ~3000 rpm (in sport or sport+ mode). It seemed that although the M235i stayed in gear, the resistance to slow the car was significantly reduced at higher rpms. I might add that I live at the bottom of a fairly steep hill about 1/4 mile long. Putting the 135is's double clutch in second gear the rpm slowly rises, but holds the speed to a maximum of 25 mph at the bottom of the hill. About half way down the hill in the M235i in second and the transmission seems to give up holding the car back after 3,000 rpm and the car begins to quickly gain speed, at the end of the hill the car was going around 40 mph!

So, here is my question; The ZF 8 speed can come with either a torque converter, electric clutch, or wet multi-pack clutch.



Does anyone know which option BMW selected for the ZF transmission installed on the M235i?

[pz619]

We have the 8HP45 ZF. It has the torque converter.

[mdputnam]

Thanks, I suspected that's what BMW selected, given the transmission's response at higher rpms.