[714BMW]

Hey guys,

I just recently purchased a 2016 M235i 6MT with 18,000 miles. Estoril Blue exterior with Black Dakota Leather fully loaded. So far the car has been amazing and the power upgrade from my 128i is awesome. I'm still relatively new to driving manual as I've only driven in my friends cars before this one, but I noticed the 1-2 shit and 3-2 downshift are pretty difficult. I was doing some research and I'm coming across horror stories of people replacing their entire ZF transmissions because of 1-2 synchros. This is kinda scary since I bought the car as is with no warranty based on people have little issues with the N55 engine until later mileage, didn't even think a BMW 6 speed would have to be worried about. Anyone know if this is a very common issue or if the stories I am coming across are fairly rare? I'd hate to have to drop near 5k to replace a whole transmission when the reason I dropped extra cash was to get one with such low miles.

I appreciate any input.

Thanks.

[jb-slow]

If it's not making grinding noises it's fine. I don't wanna sound rude but it might be you.

[XutvJet]

It's very difficult to drive these 6mts smoothly, largely due to the clutch delta valve.

To execute a smoother 1-2 shift rev up to 3500-4000rpms before shifting.

For the 3-2 downshift, quickly stab the throttle to get a good rev match. It takes practice.

Even after 31 years of driving sticks, I find that this transmission requires the most attention to execute smooth shifts. When driven in anger, this transmission is a rockstar and one of the best I've driven.

[714BMW]

Originally Posted by jb-slow

If it's not making grinding noises it's fine. I don't wanna sound rude but it might be you.

No grinding noises at all, just a little notchy is all. Was just worried about some of the stories I've heard with the 1-2 synchros but I'll just keep it mostly relaxed in those gears.

Originally Posted by XutvJet

It's very difficult to drive these 6mts smoothly, largely due to the clutch delta valve.

To execute a smoother 1-2 shift rev up to 3500-4000rpms before shifting.

For the 3-2 downshift, quickly stab the throttle to get a good rev match. It takes practice.

Even after 31 years of driving sticks, I find that this transmission requires the most attention to execute smooth shifts. When driven in anger, this transmission is a rockstar and one of the best I've driven.

Understood. Nothing more satisfying than when I get a nice rev match downshift into 2nd. The driving in anger only scares me in the 1-2nd gears because of synchro issues I've heard of. Trying to see if anyone is higher mileage with the ZF 6 speed to give me some piece of mind. I think if I just tread lightly in the 1-2 gears I'll be fine long term.

[Heitzer]

Originally Posted by 714BMW

Trying to see if anyone is higher mileage with the ZF 6 speed to give me some piece of mind. I think if I just tread lightly in the 1-2 gears I'll be fine long term.

To give you peace of mind. Mine has 122k miles on the first clutch now. This is with an LSD and altered final drive ratio which put more thrust through the driveline. Did only two track days during that time.

Its really a sturdy 6speed and can take abuse. Probably also the reason while its hard to shift and not smooth like a Honda transmission (which for me didn't last long).

[Cos270]

Originally Posted by Heitzer

To give you peace of mind. Mine has 122k miles on the first clutch now. This is with an LSD and altered final drive ratio which put more thrust through the driveline. Did only two track days during that time.

Its really a sturdy 6speed and can take abuse. Probably also the reason while its hard to shift and not smooth like a Honda transmission (which for me didn't last long).

Good to hear. I had similar worries before I purchased mine. I never launch my cars or beat on them (though they do get exercised ), and wondered if some of the failures were coming from people doing hard launches.

I agree, it has been a challenge to make smooth shifts consistently, especially going between 1-2-3. I've found that "catching" the revs as they fall just as I release the clutch past the engagement point has yielded pretty smooth shifts. Seems like that sweet spot is harder to find in those first two shifts, though.

[XutvJet]

Originally Posted by 714BMW

Understood. Nothing more satisfying than when I get a nice rev match downshift into 2nd. The driving in anger only scares me in the 1-2nd gears because of synchro issues I've heard of. Trying to see if anyone is higher mileage with the ZF 6 speed to give me some piece of mind. I think if I just tread lightly in the 1-2 gears I'll be fine long term.

Ripping a hard 1-2 shift often isn't a good idea and isn't really necessary unless you're drag racing. There is a ton torque generated due to all the torque multiplication plus all the extra torque many of us have added through mods. I keep my hard 1-2 shifts to a minimum but do hit the 2-3 shift hard fairly often. I've owned my M235 new since February 2016, have 55K miles, and the car has been pushing around 370whp and 400wtq for the last 2 years. I haven't had any issues with the clutch. I'm sure it's worn, but it's never slipped.

With the LSD, I occasionally launch the car too. The key is launching at a higher rpm, but with a bit more clutch slip and throttle modulation rather going all amateur and dumping the clutch. That's far harder on the transmission than slipping the clutch. I typically launch around 3500rpms, release the clutch just enough to feel the car start to roll, then release the clutch quickly while feeding it gas and trying to keep the rpms above 3000rpms. Around 5000-5500rpms in 1st, I can go full throttle. Launching like this results in just a scampering of tire spin. I never smell clutch either.

[jb-slow]

Know how many miles are on the fluid inside? I switched to amsoil and it made a noticable difference. Also switched to M2 trans mounts to remove some slop.

[designatedposter]

how much distance between your clutch and the floor before it engages? a common mod for these cars is a clutch pedal stopper (it's a shim under your clutch pedal to reduce clutch pedal travel). it's possible previous owner put a really big one in that prevents you from fully disengaging clutch.

https://burgertuning.com/products/bm...06-mini-cooper