Quote:
Originally Posted by R12ax7
I’ve seen on one or two threads that the difference between the manual transmission for the F30 328 and 335 is not just the different gearing, but that they are different transmissions altogether. Somewhere I read that ZF makes the 335 6MT and Getrag makes the 328 6MT (and I also know that Getrag supplies a lot of parts to ZF, but no clue in what capacity), but I cant confirm this … or even find where I read it originally.
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From BMW's TIS: the 328 utilizes GS6-17BG transmission, while 335 uses GS6-45BZ gearbox. The 17BG is indeed built by Getrag (hence "G" in the nomenclature) and 45BZ is done by Zahnradfabrik Friedrichshafen (ZF).
Besides different suppliers, the transmissions have a number of techincal differences that jumped out at me. I'll point out the ones that may affect the "shift feel" as to stay on original topic.
* Getrag gearbox uses immersion or flooded lubrication while ZF utilizes dry sump approach. According to BMW dry sump is about 2% more efficient than flooded sump. In the 17BG gearbox the gear wheels on the counter-shaft are actually submerged in oil, sloshing the lubricant uncontrollably as they rotate. In the ZF box the transmission fluid is delivered directly to gears by a pump via injection pipes. I would venture to say that this may explain certain inconsistency in the way 1-2 and 2-3 shifts feel in my 328. Sometimes they are silky smooth, sometimes they are a bit notchy.
* The syncromesh units in 335's transmission are coated with "newly developed" carbon friction lining for "improved shift quality". I have not driven a new 335 with a stick, but I would imagine that coating the synchronizers would indeed make the shifts smoother.
* The ZF transmission uses triple band syncronizers on gears 1 and 2, while Getrag's box has single band units.
The 8-speed automatic is the same for both engines: GA8HP45Z.