[mi235]

Hey guys,

My m235i might have a failing flywheel, but just wanted your opinion before I start dropping transmissions.

During take off from a stop, right at the end of the clutch/friction zone when the car is about to start moving there is a slight stutter. As if the clutch is slipping. Everything else in terms of driveability is the same, no issues of slipping clutches when the car is in motion. This issue gets worse the longer I drive the car, and the car starts to get hotter

When the car is cold (especially in the winter), there is a loud noise coming from the car, almost a rattling noise. The noise is present only when the clutch is engaged. If I depress the clutch, no noise. Engage the clutch, noise will return.

Sounds like dmfw, but let me know what you guys think

[dalderks]

I have a very similar issue with my car when pulling away from a stop (no noise though). I've never felt any clutch slippage when driving even during WOT pulls, so I'm wondering the same thing. It doesn't happen all the time, so maybe it's a different issue or in a different stage of failure. I've found cycle A/C on and off can sometimes make it go away...

Hopefully others have some experience or insight.

[mi235]

Originally Posted by dalderks

I have a very similar issue with my car when pulling away from a stop (no noise though). I've never felt any clutch slippage when driving even during WOT pulls, so I'm wondering the same thing. It doesn't happen all the time, so maybe it's a different issue or in a different stage of failure. I've found cycle A/C on and off can sometimes make it go away...

Hopefully others have some experience or insight.

Mine was in a similar situation as yours, no noise, doesn't happen all the time. But after a year of driving, it is now at the stage I am at. The noise happens only sometimes, and could only be heard when outside/windows down/no music. I used to only experience the slippage occasionally, and now it happens almost everytime.

Hopefully someone with a similar experience comments soon

[MLJR235]

Thank god someone finally posted this up lol. I felt like my noob ass just sucked at driving mt cars lol..

I noticed this seems to happen more, or at least rear its chattery head, after the car has been driven for a good while/ hot all-day driving. I assume either my flywheel has some hot spots that become pronounced when it heats up after prolonged use? That or clutch is shot? I doubt the clutch is shot as I have ZERO slip on 3-4gear full throttle inputs.

I don't drive my car daily so it is not that much of an annoyance since it doesn't really happen on short usage of the vehicle. Again, mostly starts to happen after long day use which I assume heats up oil, clutch material, and flywheel to a point that it becomes obvious.

Any expert input would be great.

[Pray for Mojo]

Mine has done this occasionally since new. It goes away for long periods, I think its from slipping it and leaving some marks on the flywheel that eventually wear away. Your clutch will also chatter at lights, but you can get it to stop by pushing it in to damp it.

[celsdogg]

I've been having the same issue for years. Like said above, it only happens when fully warmed up. It's been bugging me too. I'e had somewhat better success with a little higher engine speed before locking the clutch back up, but it isn't 100% still.

I read another thread on here the past couple of days about common issues where someone said they have also had the issue. They said that letting the clutch back in and then getting back on it again when the chattering happens helps. I haven't tried it yet.

For as similar as they seem, my wife's F30 clutch feels almost completely different and never has this issue. It seems like a somewhat common F22 thing.

[XutvJet]

Originally Posted by mi235

Hey guys,

My m235i might have a failing flywheel, but just wanted your opinion before I start dropping transmissions.

During take off from a stop, right at the end of the clutch/friction zone when the car is about to start moving there is a slight stutter. As if the clutch is slipping. Everything else in terms of driveability is the same, no issues of slipping clutches when the car is in motion. This issue gets worse the longer I drive the car, and the car starts to get hotter

When the car is cold (especially in the winter), there is a loud noise coming from the car, almost a rattling noise. The noise is present only when the clutch is engaged. If I depress the clutch, no noise. Engage the clutch, noise will return.

Sounds like dmfw, but let me know what you guys think

What driving mode are you in? Any mods like a piggyback or flash tune?

My 2016 M235 6MT has had a weird, random stumble coming right off the clutch in 1st when I'm using the "Comfort" throttle (i.e., Comfort mode, Traction mode, DSC Off mode, or Sport mode set only in Chassis). From what I can tell, it didn't show up until I started using tuners about 3 years ago; first the Dinan Sport piggyback and now the Dinantronic Stage 2 piggyback. The stumble only happens when the car is fully warmed and it's totally random. It drive me nuts because it makes me look like a total amateur stick driver (been driving sticks since the late 1980s). 99.5% of the time I drive in the Sport throttle setting and the stumble never happens.

The dual mass flywheels on these cars can be quite noisy and rattle, especially once the car is warmed up. My flywheel has been noisy for over 4.5 years. I can hear it when pulling into the garage, sometimes when shutting the car off, and very faintly from 2000-3000rpm in 1st and 2nd when using mild throttle. When I first heard it under load years ago, I was worried that it was rod knock. It's never gotten worse. Used oil analysis have been perfect throughout the years.

[celsdogg]

Originally Posted by XutvJet

What driving mode are you in? Any mods like a piggyback or flash tune?

My 2016 M235 6MT has had a weird, random stumble coming right off the clutch in 1st when I'm using the "Comfort" throttle (i.e., Comfort mode, Traction mode, DSC Off mode, or Sport mode set only in Chassis). From what I can tell, it didn't show up until I started using tuners about 3 years ago; first the Dinan Sport piggyback and now the Dinantronic Stage 2 piggyback. The stumble only happens when the car is fully warmed and it's totally random. It drive me nuts because it makes me look like a total amateur stick driver (been driving sticks since the late 1980s). 99.5% of the time I drive in the Sport throttle setting and the stumble never happens.

The dual mass flywheels on these cars can be quite noisy and rattle, especially once the car is warmed up. My flywheel has been noisy for over 4.5 years. I can hear it when pulling into the garage, sometimes when shutting the car off, and very faintly from 2000-3000rpm in 1st and 2nd when using mild throttle. When I first heard it under load years ago, I was worried that it was rod knock. It's never gotten worse. Used oil analysis have been perfect throughout the years.

Jet, I think it was you who said that letting off and on the clutch when it happens reduces it. Perhaps it was from a tune. I got this car with 14k on it, but I have a feeling that the PO had it tuned.

I have the stumble in sport. I pretty much only drive it in sport. i also hate how it makes me look like an amateur; its even worse since I have a decal for "The Manual Gearbox Preservation Society" on my rear window.

BMW has had some DMF noise for a long time. My E30, F22, and long gone E46 all had it. Its kinda part of the character of a BMW MT for me.

[mi235]

Seems like a common issue,

The interesting thing is, the m235i has a unique flywheel compared to all the other n55 cars. It has a different bmw part number, but from my understanding it f22s share the same engine and trans as the f30s?

I am tuned on bm3 stage 1, stock everything. But I've had the issue before the tune and after the tune. Issue is there no matter what drive mode I'm in, comfort, sport and sport+.

I am about to replace flywheel and clutch with oem parts, but I'm worried it's going to have the exact same issue after spending thousands of dollars.

[MLJR235]

I have a feeling some of the issue or extra noise we experience is from too much input from us drivers off initial take-off/ clutch work from a dead stop.

Over the last few years I have modded, in the transmission dept;

*OEM transmission mounts= Rogue ssk with higher durometer mounts
*CDV Deleted from slave cylinder
*Clutch pedal spring removed
*Shifter cradle rear and front from oem rubber to poly bushings.

The combination of mods led to more feedback from underneath up to the pedal and cabin as now I can better hear & feel what is going on, slight increase in noise is not always a bad thing. The oem build of bushings and mounts are extremely soft and hide/ absorb a large amount of noise and feel which may actually be beneficial to us MT drivers.

Before, I would have to always rev to about 1200-1500 rpm to get off the line somewhat smoothly. Now, I can let off at almost idle 600-1000 rpm without a hitch. I can hear and feel as soon as the clutch starts grabbing which helps manipulate clutch vs rpm more effectively.

Aside from this, I believe the OP is trying to get at that sometimes the flywheel/clutch becomes MORE chattery when hot or at random intervals?

I too experience some "slipping" or chatter after the car is hot from all-day use. I rarely get any off-the-line chatter when cold or on short trips where the vehicle has not been used much during the day.

Again, possibly due to hot spots or warped flywheel?

[mi235]

It seems it's a common issue that everyone has lived with lol.

It probably is a hot spot/warped disk/worn springs in the dmfw but if it's so common it may happen again even if I were to replace the flywheel.

I only have 40k miles on this car, some even stated experiencing this issue from brand new, it very well might be a design flaw.

Since no one has actually replaced the flywheel and reported back how the car feels with the new flywheel over a longer period of time, it's all speculation.

But knowing that it is a common issue, I may hold of on getting a new flywheel for now.

[XutvJet]

Originally Posted by mi235

Seems like a common issue,

The interesting thing is, the m235i has a unique flywheel compared to all the other n55 cars. It has a different bmw part number, but from my understanding it f22s share the same engine and trans as the f30s?

In addition to the different flywheel, the N55 in the M235 is slightly different from other 2014+ N55s in that it has a forged crank compared to the cast crank in other N55s minus the M2 N55 (uses the same forged crank). The M235 also has an oil cooler were as other N55s don't (minus the M2 which has the same cooler).

All 2014+ N55s in the F series cars have electronic wastegates, S55 forged rods, and rod bearings. The 2013 and below N55s has occasional issues with spun rod bearings. This doesn't seem to be much of an issue with the 2014+ EWG-equipped N55s.

The M2 N55 also has piston oil squinters, S55 piston rings, a better oil pickup and baffling system for high G driving, and stronger 1-2 and 2-3 syncros in the 6MT.

[XutvJet]

Originally Posted by mi235

I am about to replace flywheel and clutch with oem parts, but I'm worried it's going to have the exact same issue after spending thousands of dollars.

Is your issue all the time or random?

I think the issue is the result of clutch delay valve (CDV) and throttle and power tuning. I plan to get rid of the CDV this summer.

Here's my complaint back in 2016: https://www.2addicts.com/forums/show....php?t=1298738

[MLJR235]

Originally Posted by XutvJet

Is your issue all the time or random?

I think the issue is the result of clutch delay valve (CDV) and throttle and power tuning. I plan to get rid of the CDV this summer.

Here's my complaint back in 2016: https://www.2addicts.com/forums/show....php?t=1298738

CDV delete helps immensely. Makes rolling off in 1st gear more consistent and predictable for sure.

[knuckalicious]

wow I've had my car for almost two years and this problem has been bugging me since the start. I was starting to doubt my driving abilities as well but I'm glad I finally found I'm not the only one dealing with this.

[AmuroRay]

Same thing -

https://www.2addicts.com/forums/show....php?t=1699405

Still happens, I feel like the clutch gets stiffer/sticky when I do quick hard shifts. Glad to know I'm not the only one.

[XutvJet]

I firmly believe BMW makes the 6MTs have such wonky issues that they're trying to sway people to buy automatics. They would love that because then they have full control of what the user can and can't do when it comes to shifting (i.e., no misshifts) and it helps them maximize profit.

My frustrations with the 6MT are many:

- The weird, random stumble
- Very occasional and random chatter in 1st
- Hard to smoothly execute a 1-2 shift during normal driving. I've learned that shifting above 3500rpms helps significantly.
- The high resting clutch pedal. Remedied with the Ultimate Clutch Pedal which lowers the pedal to even with the brake pedal.
- The damn CDV which makes the clutch point shift around slightly
- Weird, random throttle rise where I'm giving it normal throttle when starting out in 1st, but the rpms shoot up by twice as much than I'm expecting (commanding 1,500rpms and the rpms go to 2,500-3,000rpms). The fix is to release the throttle and clutch in and try again. It happens maybe once or twice month and has done it for 4+ years.

With all that said, I wouldn't own an automatic or DCT (M2). It's just too boring after a few months. I've made that mistake twice in the past. I'm seriously considering an N55 M2 and it will definitely be a 6MT.

When driven in anger, I find this 6MT to be quite good. I normally avoid slamming the 1-2 shift at full throttle as I know the 1-2 synchro is not super strong. I can count the number of times I've fully ripped the 1-2 shift on two hands over the past 5+ years of ownership. I rip the 2-3 and 3-4 routinely.

[MLJR235]

Originally Posted by XutvJet

I firmly believe BMW makes the 6MTs have such wonky issues that they're trying to sway people to buy automatics. They would love that because then they have full control of what the user can and can't do when it comes to shifting (i.e., no misshifts) and it helps them maximize profit.

My frustrations with the 6MT are many:

- The weird, random stumble
- Very occasional and random chatter in 1st
- Hard to smoothly execute a 1-2 shift during normal driving. I've learned that shifting above 3500rpms helps significantly.
- The high resting clutch pedal. Remedied with the Ultimate Clutch Pedal which lowers the pedal to even with the brake pedal.
- The damn CDV which makes the clutch point shift around slightly
- Weird, random throttle rise where I'm giving it normal throttle when starting out in 1st, but the rpms shoot up by twice as much than I'm expecting (commanding 1,500rpms and the rpms go to 2,500-3,000rpms). The fix is to release the throttle and clutch in and try again. It happens maybe once or twice month and has done it for 4+ years.

With all that said, I wouldn't own an automatic or DCT (M2). It's just too boring after a few months. I've made that mistake twice in the past. I'm seriously considering an N55 M2 and it will definitely be a 6MT.

When driven in anger, I find this 6MT to be quite good. I normally avoid slamming the 1-2 shift at full throttle as I know the 1-2 synchro is not super strong. I can count the number of times I've fully ripped the 1-2 shift on two hands over the past 5+ years of ownership. I rip the 2-3 and 3-4 routinely.

You make valid points and fully agree because I experienced similar behavior.

In OEM form I dreaded 1-2 shifts and off the line take offs were a joke. In my current moded form, I can't say enough how much better the car is to drive, probably sound like a broker record now.

For all that want to improve your experience, I highly recommend CDV delete, rogue engineering rubber transmission mounts, and possibly the biggest improvement was the short shift kit we got on the group buy from Rogue. Every single person who did the ssk swap will tell you the same thing, it transforms the car for the better.

In short, our mt 235's are not doomed to be wonky forever. We can make them fun daily's with small meaningful mods. Everything you need to know on every mod i mentioned can be found right here on 2addicts which why i love this forum. There's soo much good info compared to other sites

[XutvJet]

^Agreed.

I added the M Performance shift knob which made the shifting feel more direct and the shift throw feel shorter (though it's really not) and also added the M2 transmission mounts which are stiffer than the M235 mounts.

Can't wait to get rid of the CDV (or get a 2018 M2 )

[AmuroRay]

If they flywheel is a unique part number to the M235i, It could be "lighter weight" and that could explain why it rattles more than the one in the 335i/435i.

[XutvJet]

Originally Posted by AmuroRay

If they flywheel is a unique part number to the M235i, It could be "lighter weight" and that could explain why it rattles more than the one in the 335i/435i.

Bet you're right. The M2 runs a lighter one too.

[MLJR235]

Originally Posted by XutvJet

Quote:
Originally Posted by AmuroRay View Post
If they flywheel is a unique part number to the M235i, It could be "lighter weight" and that could explain why it rattles more than the one in the 335i/435i.

Bet you're right. The M2 runs a lighter one too.Bet you're right. The M2 runs a lighter one too.

I feel special now lol