Modern car companies fundamentally do 3 things: make engines, make transmissions, and assembly parts into cars. Nearly everything else is outsourced. These are all expensive complex things that little companies cannot make. They don't make their own seats, alternators, tires... (Honda is an exception to the above rule in general).
Which wasn't such a great idea if you ask me. WHy bother with seats if they can just be bought from suppliers specializing in seats? Same for manufacturing. It puzzles me why Tesla did not outsource Model 3 production to a company like Magna or Valmet. Both of them are producing Mercedes, Ford, Porsche, Peugeot, Opel, BMW at a lot of others on the same assembly lines. And you can be sure that this production is running smoothly without a CEO living on the shop floor or meeting volume targets at the cost of quality. If that would be the case, these sub-contractors would be out of business already.
And there are reasons for that as well, usually the risk share form these outsourcing activities is very favorable for car makers. As a sidenote they also outsource a lot of engineering work, at leat in Germany. And that implies a risk for traditional caqr makers way beyond competitors like Tesla. FOr an EV half the activities performed by tradintional car makers is not needed anymore. That impacts head-count, unions, sites, you name it. At the same time the externally produced value per car is further increasing, giving the electric drive train supplier a lot of power through the automotive supply chain. So the biggest challenge for traditional car makers is to remain the most important automotive players while developing EVs of there own. As long as that position is maintained they will do just fine, production is not their problem, neither is money (at least so for).
The ZF 6HP automatic was a game changer when it was released. It had six forward gears with the ability to lock the torque converter in any gear and it was cheaper to produce than most four speed transmissions. They ended up dominating the RWD automatic transmission market.
I have a 335i with a 6HP21, and the converter lockup behavior was the first thing I noticed when I got the car. It usually locks up in first gear, which I’m sure helps with fuel economy a lot.
That said, the overall shift quality could be a little better, IMO. I’m no transmission expert, but I think it basically shifts “clutch-to-clutch” instead of using sprags like a traditional automatic, so it’s really sensitive to timings. If the second clutch engages too late, it’s in neutral for a bit. If it engages to early, it’s in two gears at the same time.
For example, if you’re accelerating lightly and it’s about to shift, then you suddenly have to hit the accelerator harder, sometimes it feels like it has already committed to shifting under the lighter load and it almost feels like it’s in neutral for a split second before banging into the next gear.
Not sure how much of this is related to the BMW shift maps or the transmission itself.
All that said, the transmission has proven to be very reliable. People in the 335i community are putting well over 500 ft-lbs of torque through them and they seem to be holding up, and my car has 211,000 miles and it shifts the same as it did when I got it with 40,000 miles.
Also, people with newer 5.0 Mustangs don’t seem to have many complaints, and it’s basically the same transmission.
