[Rob@RBTurbo]

Ok I am in the market for a 335i, particularly the sedan (although I dont think it matters). I am leaning towards an automatic, as they have obvious advantages in high performance Turbocharged applications along with ease of driving especially when you have kids/etc. But I am not totally against a manual either. My concern is getting one that is reliable, especially when it comes to higher power applications and modding.

Id like to know what people have either experienced firsthand, witnessed, been told, whatever, about failures or even about speculations with either type of Trans and what they can handle. Usually with a manual gearbox they are pretty stout, and the primary concern is either the 1) Clutch being small and prematurely slipping or 2) Synchronizers being fragile.

Thanks for any insight you may provide.

Rob

[OpenFlash]

Both the 6AT and 6MT are perfectly durable in tuned applications. The 6AT is geared better for 1/4 mile acceleration. It's also a great AT. But MTs, in my opinion are more fun. Boils down to personal driving preference as they both make perfectly viable alternatives.

Shiv

[Vince@ V K Motorwerks]

Originally Posted by RobBeck

Ok I am in the market for a 335i, particularly the sedan (although I dont think it matters). I am leaning towards an automatic, as they have obvious advantages in high performance Turbocharged applications along with ease of driving especially when you have kids/etc. But I am not totally against a manual either. My concern is getting one that is reliable, especially when it comes to higher power applications and modding.

Id like to know what people have either experienced firsthand, witnessed, been told, whatever, about failures or even about speculations with either type of Trans and what they can handle. Usually with a manual gearbox they are pretty stout, and the primary concern is either the 1) Clutch being small and prematurely slipping or 2) Synchronizers being fragile.

Thanks for any insight you may provide.

Rob

I dont think I have heard of any of these transmissions failing as of yet. I dont think anyone has been brave enough or has had the ability to actually determine the max load either of these transmissions can handle. I know this has been discussed in various threads. Most tuners it seems are keeping max tq numbers at around 400 to the wheels as a safty precaution.

[Rob@RBTurbo]

Thanks for the feedback guys. What diameter is the clutch on the manuals? Is it just a typical organic single disc?

[BavarianBullet]

Originally Posted by RobBeck

Thanks for the feedback guys. What diameter is the clutch on the manuals? Is it just a typical organic single disc?

I have the 6MT and if I could do it again I'd go 6AT just in this car. The 6MT kinda sucks. Worst one I've had in any car thus far.

The Shifter is so sloppy you need to spend $$$ to replace it with something that works and of course the knob will come off if you pull 1-2 hard enough. (WTF?)

It seems to vary a bit by car but a lot of people have issues with the 1-2 shift going into 2nd gear, myself included.

Then there's the nanny clutch delay valve which restricts the speed at which the clutch can return (clamp), presumably to avoid trans damage. The net result is you need to get under the car and take it out if you want to shift at anything other than grandfatherly speeds (or it will jerk the whole car around like you don't know how to drive).

BB

[Ironring Racing]

I asked Steve Dinan specifically about the transmissions before Christmas. He said BMW's tranies are spec'd based on the tourque rating of the car. He said 300lft-lb is the top cut-off, with everything in that and higher power range getting the same 6MT (meaning the 335 has the same 6MT as the M5/M6). I only asked about the manuals, didn't ask about the AT. One tuner posted on here that they felt the 6AT was limited by the transmission control unit to a max 400ft-lbs, but I haven't seen anything from them lately so don't know if they proved that thoery or not.

I currently actually own both a 6AT and a 6MT. I originally bought the 6AT after driving students 335's (I'm a BMW driving instructor) the first year they came out. I felt it was a great car, on par with the current M3 (E46).

But of course you only drive a students car at a certain pace, not hard, and when I got out on the track the next year with my 6AT I was imediately dissapointed. It won't hold at redline which is annoying, if not a little dangerous, when you're mid corner and it shifts on you. I'd much rather it hold at redline and I control when it shifts. Additionally, because of that, I found "manual/paddle" shifting was quite useless. I kept getting double upshifts (it would shift up 2 gears), because I'd hit the up shift button at the same time the car shifted at redline, and it would register 2 shifts, one it's own and the other mine. When you've pushed hard to gain on that 911 S and it jumps you up 2 gears just as you're coming onto the straight... grrrrrrrr.

For the road, it's a good auto. My only complaint is it lags just a bit and then hits, which, if you're not adjusting for it, makes for a jolt for the passengers. It was somewhat an issue with the hill hold function that I beleive is fixed with new cars or new Progman versions. Otherwise, no complaints about the auto in normal driving.

The manual solves all the above track issues, and I love heel-toe, so it put a big smile back on my face when I bought the 6MT. I did the clutch delay valve (CDV) delete, but quite honestly, I can't say as I've noticed any difference. Some say they have, I didn't. But the 6MT is not without issues. The 1-2 shifts, especially first thing on a cold morning, or on the drag strip, will grind rather than slip in more than occasionally. I'd blame it on the 1-2 syncro, but it's not regular by any standard. It did it before and after the CDV delete, no difference. Also, the stock shifter is kind of rubbery. I put in the 330i short shift kit, just bought the specific parts I needed ($60 total), and I love it. It requires more force (by defenition it will), but is more positive and a nice short throw. There's other SSK's out there, including BMW's own, which are 10x the price. Haven't driven any of them, but I have a hard time believing they are 10x better.

I also agree with the above post that, even with the CDV, the clutch doesn't exactly drop, and the engagement does seem artificially slow, whether it's software or mechanically slow, when you shift quickly and release the clutch pedal, the revs don't match immediately. It almost feels like the clutch is slipping, but since it does this in all shifts (i.e. 3-4), and the clutch is solid in all other situations (launches from a standstill, drifting, etc.) I don't think it's the clutch slipping. I come from dry clutch superbikes, shifter karts, some Legends cars, etc, so I'm used to quick, positive clutches, so maybe I'm being a little hard. Also, my previous car was an RSX-S, which has a great clutch, so again, maybe not a fair comparison.

Hopefully that's a reasonable comparison of the 2 transmissions. If you're not going to the track, the flappy paddle is probably going to make your life easier. If you're a gear-head, track day/drifter, stop-light drag racer, even though the 6AT may be qeared a little quicker, the manual is so much more involving and puts a much bigger smile on my face. Like I said, I've still got both, and everytime I go back to the auto, I'm firmly and quickly reminded of why I bought the second one.

If you're the latter, I highly recommend you install a LSD. Especially if you enjoy power oversteer. :-)

[yamsta]

Originally Posted by BavarianBullet

I have the 6MT and if I could do it again I'd go 6AT just in this car. The 6MT kinda sucks. Worst one I've had in any car thus far.

The Shifter is so sloppy you need to spend $$$ to replace it with something that works and of course the knob will come off if you pull 1-2 hard enough. (WTF?)

It seems to vary a bit by car but a lot of people have issues with the 1-2 shift going into 2nd gear, myself included.

Then there's the nanny clutch delay valve which restricts the speed at which the clutch can return (clamp), presumably to avoid trans damage. The net result is you need to get under the car and take it out if you want to shift at anything other than grandfatherly speeds (or it will jerk the whole car around like you don't know how to drive).

BB

I have a 6MT and It was true that the 1-2 shift was very tough until i got the OEM 335i Short Shift Kit...after I got the kit installed and modified the CDV shifting was MUCH improved. Yes, you have to shell out some $$$ in order to get the SSK+installation but IIRC the 6AT costs more than the 6MT. But at the end of the day its really up what your tastes/preferences are....

--yamsta

[XPO186]

MT is definitely more fun/engaging... I love running through the gears on on-ramps and downshifting to pass etc. I only *slightly* regret getting MT when dealing with stop/go traffic.

IMO the CDV+SSK combo is a must. Shifter and clutch feel is so much more positive and I like the notchy feeling in the gear box.

@Ironring: My 2nd gear also occasionally grinds right after cold starts... I find I have to baby the shifter a little bit while the car warms up and after that it's fine.

[Rob@RBTurbo]

Great information guys. Ironring, makes perfect sense what youve said... and humorous at points too! ha.

All in all, from what Ive gathered, is that it really doesnt matter too much from a power capacity perspective; at least of whats known thus far. I like the ease of driving (ie. kids, daily driver, traffic jams, etc) of the auto. I also like the fact of keeping an auto in Turbocharged applications, as the WOT the whole time keeps you in boost the whole time. Unlike the manual, where to match that you must no lift shift which is risky business on the synchros and clutch..... otherwise if you lift surely you are deflating your induction system and having to boost it back up after you get back into it. With these tiny turbos, it probably isnt killing you... right now.

On the flip side. I too love the control of the manual, but its not end all be all to me. Like Ironring said, you have a computer wanting to do something and if you do something too its counterproductive (yeah Id be ticked off too!!). But if that happened to me Id probably just leave well enough alone and let the computer shift the car or get its points calibrated (if possible) to do what Id like it to do. But with the manual, its of no concern... you are in ultimate control and yeah of course rowing gears definitely makes driving more exhilirating. All in all I can see how the manual would be the way to go on a road course, but that wouldnt be my purpose with the car. It would be moreso just a daily driver, one that exhibits enough power to keep a smile on my face. It also would see occasional drag use, potentially. I still am not sure I know enough about the clutch on the manual, if its really going to start falling apart or not. Usually, alot can be said for the diameter of the disc... if its a standard single organic disc like most vehicles anyway. If so, Id hope it was 11"+. This in itself would be a deterent if it had a small disc in it, just not worth the grief IMO.