[K8_M235i]

Hello Everyone,

My car, a 2016 M235i 6MT, recently developed a strange issue in between high rpm (>5000) gear changes. Originally I thought I was having the same issue that people were reporting in this thread.
https://www.2addicts.com/forums/show....php?t=1008811 .

A quick summary is: A grind going into 2nd with moderate throttle while shifting at higher rpms. There were a few other members that expressed similar conditions and also had transmissions replaced.

My issue is almost identical except for the fact that it will vibrate audibly the second I clutch-in before even trying to go into 2nd. I also get a lot of the same feedback through the shifter and the clutch pedal. It will continue to vibrate even if I keep the gear selector in first and just let the rpms drop while clutched in. If I do actually shift into 2nd there is more of a harsh grind that I can feel and hear as well.

It will also do the same exact thing during a 2nd to 3rd shift. Not sure about 3rd to 4th because I would have to be going pretty quick to test it out.


To map it out and hopefully be less confusing, here is a sequence of events.

-Quick/moderate acceleration in 1st to 5000rpms

-Clutch in

*vibration starts

-Keep gear selector in 1st and clutch in, vibration continues until rpms drop
OR
-Shift into second

*audible grind

-Clutch in

*Now in second, everything feels normal


This is all at operation temp while driving normally, not slow, but also not banging gears in full boost.

From what I've gathered from the other thread and from my general knowledge, the clutch-in vibration almost feels like the clutch not releasing fully, and the grind going into gear seems like it could be a result of this added stress on the synchros. This was someone else's theory in the linked thread as well.

I called BMW today, but I couldn't really explain that much to the person who answers the phones. I'm waiting for a call from my advisor so I can explain a bit more. I have an appointment in 2 weeks, but hopefully I can go in sooner just to show them the issue.

Any feedback would be appreciated.

Thanks,

[overcoil]

How many miles on car ?

Throw out bearing ? Not a big deal really, clutches wear out.

[K8_M235i]

Originally Posted by ScottSinger

How many miles on car ?

Throw out bearing ? Not a big deal really, clutches wear out.

34k. A possibility, but it seems unlikely to me based on the thread with everyone else's similarities.

I've had cars with bad throwout bearings, so I'm familiar with that sound and feeling.

I also wouldn't expect the clutch to be worn to that extent.

[overcoil]

Originally Posted by K8_M235i

34k. A possibility, but it seems unlikely to me based on the thread with everyone else's similarities.

I've had cars with bad throwout bearings, so I'm familiar with that sound and feeling.

I also wouldn't expect the clutch to be worn to that extent.

Yeah I would think clutch in normal driving going close to 100k miles.

Am I correct that your noise coincided with clutch pedal movement and not with gear shift lever actuation ?

[K8_M235i]

Originally Posted by ScottSinger

Yeah I would think clutch in normal driving going close to 100k miles.

Am I correct that your noise coincided with clutch pedal movement and not with gear shift lever actuation ?

The vibration is with the clutch fully depressed, not while moving up and down. I feel it in the clutch and the shifter so I'm guessing the whole trans is vibrating.

[amw896]

I place my bet on a loose pressure plate or dmf.

[K8_M235i]

Originally Posted by amw896

I place my bet on a loose pressure plate or dmf.

The flywheel did cross my mind too

[SteveInfante]

I'm not sure how much different the N20 6MT is from the N55 but I was having some of those issues at around 58K miles, I'm at 73K now. I no longer have them after switching my transmission fluid from the stock stuff to RedLine DT4. Shifts are much smoother now and there's no shudder like there was before. The 1st to 2nd shift at 5000 and up is like butter in the fact that it's no longer notchy like it was before. I initially thought I was going to be changing the clutch/DMF/PP/TOB but I'm pretty certain I have plenty of miles left till I have to tackle that. I don't drive my car slow, it's my daily, and gets lots of heel/toe action on a regular basis.

[amw896]

Originally Posted by SteveInfante

I'm not sure how much different the N20 6MT is from the N55 but I was having some of those issues at around 58K miles, I'm at 73K now. I no longer have them after switching my transmission fluid from the stock stuff to RedLine DT4. Shifts are much smoother now and there's no shudder like there was before. The 1st to 2nd shift at 5000 and up is like butter in the fact that it's no longer notchy like it was before. I initially thought I was going to be changing the clutch/DMF/PP/TOB but I'm pretty certain I have plenty of miles left till I have to tackle that. I don't drive my car slow, it's my daily, and gets lots of heel/toe action on a regular basis.

good call!! I also seen a couple posts about initial factory refills being a bit short of fluid.

[dradernh]

Originally Posted by SteveInfante

...[switch] transmission fluid from the stock stuff to RedLine DT4.

^ This.

Red Line's MTL 75W80 is another option that has been shown to work in BMWs (and the wife's Mazda 3, too! :-): https://www.redlineoil.com/gear-oil-...-transmissions

[amw896]

Originally Posted by dradernh

^ This.

Red Line's MTL 75W80 is another option that has been shown to work in BMWs (and the wife's Mazda 3, too! :-): https://www.redlineoil.com/gear-oil-for-manual-transmissions

what's the diff? I don't know much about trans fluids.

[dradernh]

Originally Posted by amw896

what's the diff? I don't know much about trans fluids.

I don't really know. The shops I've used for both race BMWs and a street BMW (and a current model Mazda 3) have used one or the other of those fluids. The better of the shops used the MTL in a race E36 M3 and in the Mazda 3's transaxle.

Red Line has a couple of pages that might help answer your question:

https://www.redlineoil.com/faq
https://www.redlineoil.com/technical-info

You can also contact Red Line directly via their online contact form or by phone if you want to speak to a technical person. Red Line is a product line for professionals and for enthusiasts like us, so a phone conversation isn't out of the question. Might as well get it straight from the horse's mouth, right?

[SteveInfante]

Originally Posted by amw896

what's the diff? I don't know much about trans fluids.

Well Chad from Morehead Speed Works here in Columbia runs that in all the Spec E46 racecars he builds at his shop. I trust his judgement.

[K8_M235i]

Originally Posted by SteveInfante

I'm not sure how much different the N20 6MT is from the N55 but I was having some of those issues at around 58K miles, I'm at 73K now. I no longer have them after switching my transmission fluid from the stock stuff to RedLine DT4. Shifts are much smoother now and there's no shudder like there was before. The 1st to 2nd shift at 5000 and up is like butter in the fact that it's no longer notchy like it was before. I initially thought I was going to be changing the clutch/DMF/PP/TOB but I'm pretty certain I have plenty of miles left till I have to tackle that. I don't drive my car slow, it's my daily, and gets lots of heel/toe action on a regular basis.

Thanks for the suggestion.

I have heard of people liking that fluid to smooth things out. In my case I feel like it might be a bigger issue than fluid though. To put it in classy terms, it seems very f*cked up.

The vibration is so violent that the whole car feels like it has massaging seats. The grind is so loud that it can definitely be heard by everyone in the car, probably the people in the car next to me too. It makes me cringe. I feel bad for my car.

When everything gets resolved I will definitely have the fluid changed to the redline by a reputable indy BMW shop. I would hate to think that the fluid caused it in the first place.



BMW still hasn't gotten back to me to let me know if I can bring it by just to show them before my appointment. Until then, slow shifts under 4k rpm.

[Dylan86]

Definitely starting to sounds like a rotational issue. The DMF failure being my first bet, and a broken or loose PP, being my second.

Hope you get her sorted out man, these situations suck!

[K8_M235i]

I was able to push my appointment forward to next Wednesday. Better than 2 weeks

[MarcoZandrini]

Originally Posted by K8_M235i

Thanks for the suggestion.

I have heard of people liking that fluid to smooth things out. In my case I feel like it might be a bigger issue than fluid though. To put it in classy terms, it seems very f*cked up.

The vibration is so violent that the whole car feels like it has massaging seats. The grind is so loud that it can definitely be heard by everyone in the car, probably the people in the car next to me too. It makes me cringe. I feel bad for my car.

When everything gets resolved I will definitely have the fluid changed to the redline by a reputable indy BMW shop. I would hate to think that the fluid caused it in the first place.



BMW still hasn't gotten back to me to let me know if I can bring it by just to show them before my appointment. Until then, slow shifts under 4k rpm.

Could be a bad engine or transmission mount.

[Wheelwright]

If it grinds it means your transmission's synchro or synchros are damaged. The only real remedy is to replace the transmission, adding Redline will only delay the inevitable. Your clutch and flywheel may also be damaged which warranty doesn't cover (hopefully you won't get screwed on those like I was to the tune of 4800 dollars). Good luck and I hope your dealer/BMW will accommodate you.

[K8_M235i]

Originally Posted by Wheelwright

If it grinds it means your transmission's synchro or synchros are damaged. The only real remedy is to replace the transmission, adding Redline will only delay the inevitable. Your clutch and flywheel may also be damaged which warranty doesn't cover (hopefully you won't get screwed on those like I was to the tune of 4800 dollars). Good luck and I hope your dealer/BMW will accommodate you.

Did you have a similar issue that warranted the clutch and flywheel?

I'd like to think that if a problem caused the clutch to get damaged that it would be covered as well.

[Wheelwright]

Originally Posted by K8_M235i

Did you have a similar issue that warranted the clutch and flywheel?

I'd like to think that if a problem caused the clutch to get damaged that it would be covered as well.

In my case it most likely caused clutch & flywheel damage (I know how to operate manual transmission car so it wasn't me), however all my explanation and pleading fell on deaf ears so I only ended up with an outrageously inflated bill.

[K8_M235i]

Originally Posted by Wheelwright

In my case it most likely caused clutch & flywheel damage (I know how to operate manual transmission car so it wasn't me), however all my explanation and pleading fell on deaf ears so I only ended up with an outrageously inflated bill.

Ouch. I really don't understand the clutch cost on these cars.

My car is under CPO warranty and I upgraded the maintenance as well, so I hope I don't run into these issues.

Like you said, I too know how to drive manual well and this isn't my first manual car. Frustrating.

[K8_M235i]

So a little update:

Dropped my car off Thursday and it spent the weekend at the dealer while I was at the Montreal Grand Prix (which was awesome).

They claim that it was a malfunctioning clutch assembly. They wouldn't really go into detail on the phone. It's frustrating since 95% of their customers don't know anything about cars, so they assume that I, and others who are into cars don't either.

They did tell me that it wasn't replaced for wear, so I'm guessing it was the pressure plate.

I'm questioning whether or not they tried to diagnose if there is a actually transmission issue or they are just throwing a clutch at it. We'll see tomorrow.

They made it clear that if the issue is still there they will replace more stuff.

Good news is my maintenance plan already paid for itself with this clutch.