1st to 2nd grind at high rpm

[JCtx]

Originally Posted by BMW M Power Mexico

Has anyone tried a different gearbox oil? Red Line? Did it make any difference?

All I can say is Redline MTL, which is the same 'special' oil (basically 5/30 oil with different additives) recommended by Honda and BMW, made quite a difference on a new '08 Honda Accord 6MT I use as a DD. That car has the best shifting tranny I've ever tried, and I've driven/owned plenty of manual cars in my life, including Porsches (which also use cable linkages), Vettes, and BMWs. My Honda had the same notchy 1-2 shift, especially when cold, and Redline fixed it. Huge difference when cold, and subtle but noticeable when hot. MTL was like water compared to the Honda fluid, which explains cold notchiness. MTL clalims slippery stuff is not the best for synchros, that their formula has the perfect viscosity. I've never been brand loyal on anything, and never will. I give credit where it's due. Redline happened to have the only oil specifically formulated for Hondas (and BMWs), and that's why I used it. I never used it before, nor I plan to except for the tranny.

Having said all of that, I changed it on my Honda at 900 miles because I pay for maintenance, and it's a lot cheaper (and more reliable) than BMW, so I don't fear having an issue with warranty. On my M3, I rather not change the oil until somebody personally vouches for MTL, since BMW pays for service, and putting something different could turn into a hassle if something was to happen to my tranny. Yeah, I know about Magnusson and Moss, but I'm not going to potentially fight a corporate lawyer over an issue that's not really a problem, but an annoyance.

If I still lived in Mexico City like you (I lived in 'La Herradura', near Tecamachalco, 25 years ago), where I assume you have no maintenance agreement, I'd try it in a heartbeat. If my Honda is any indication, it should make a noticeable difference, since both trannies use the same oil, and I had exactly the same 'problem' on my Honda. By the way, the precision and mechanical feel of that shifter is something a stock M3 can only dream of, even with diferent oil. That's one of my small disappointments with my M3; it should have had a better shifter, and better shifter action IMO (I know an SSK improves things, but don't want the extra noise). Porsche's shifter is better, but far from perfect too, but at least they have the excuse of being a cable linkage. Sorry for the long-winded post. Good luck man, and if you change the fluid, please post your results. If positive, I'd change it on my M3 immediately. Thanks.

[oneginee]

^

higher gearbox oil viscosity is only a band aid fix for this problem in my opinion. The problem is in the dual disc clutch not the gearbox. The synchro grinding noise is only the result not the cause of failed clutch disengagement (see my previous post ?). More slippery oil will reduce the grind noise but may not be formulated correctly for this MT. Your honda was not a dual disc clutch like the M3. I think it would be hazardous to put redline oil in the M3 MT. That said your input was interesting to read.

[auggiem3]

I'm glad I found this thread...after driving (and racing) the e46 6spd manual M3 for 6 years and prior to that 4 years in a manual S4, I thought I was having a mental lapse on clutch usage. That being said, I have experienced this issue in 4 separate '08/'09 M3's - the car I test drove, the M3 I drove at the performance center, my car and my buddy's '09.

Everyone I know accustomed to a quick 1-2 shift in other BMWs ends up with a handful of grind at some point in the e92...sucks, but slowing it down does make the difference.

[MMMorish]

Took my car to the dealer today to get a tech to drive it and he got a grind!! Twice!!!

Dealer has now ordered a new tranny and will be installing one in my car whenever it gets in.

[farbarg]

Originally Posted by MMMorish

Took my car to the dealer today to get a tech to drive it and he got a grind!! Twice!!!

Dealer has now ordered a new tranny and will be installing one in my car whenever it gets in.

Wow. Glad they're looking after you. Clearly, some cars have this worse than others. I'm not sure I could make it happen on demand; I've been slowing my 1-2 shifts which has definitely helped.

[TUNEDM3]

Originally Posted by MMMorish

Took my car to the dealer today to get a tech to drive it and he got a grind!! Twice!!!

Dealer has now ordered a new tranny and will be installing one in my car whenever it gets in.

Good for you, I hope it fixes the problem. But the tranny would not fix the problem if the problem lies with the car having a dual clutch. Now that its brought to my attention it really does seem to be the issue.

[farbarg]

Originally Posted by TUNEDM3

Good for you, I hope it fixes the problem. But the tranny would not fix the problem if the problem lies with the car having a dual clutch. Now that its brought to my attention it really does seem to be the issue.

You mean dual-mass fly wheel? This is an MT issue.

[TUNEDM3]

Originally Posted by farbarg

You mean dual-mass fly wheel? This is an MT issue.

Whoops...Yes I meant the dual-mass flywheel. If the problem lies within the clutch and flywheel how would a new tranny fix the issue?

[MMMorish]

Originally Posted by TUNEDM3

Whoops...Yes I meant the dual-mass flywheel. If the problem lies within the clutch and flywheel how would a new tranny fix the issue?

I wonder, if they're replacing the tranny, wouldn't they replace the flywheel and clutch too?

Originally Posted by TUNEDM3

Good for you, I hope it fixes the problem. But the tranny would not fix the problem if the problem lies with the car having a dual clutch. Now that its brought to my attention it really does seem to be the issue.

I guess I'll have to wait and see what happens when I get the new tranny.

Originally Posted by farbarg

Wow. Glad they're looking after you. Clearly, some cars have this worse than others. I'm not sure I could make it happen on demand; I've been slowing my 1-2 shifts which has definitely helped.

Mine only happens on quick shifts. Slow shifts won't cause it. Still, it's nice to know I'll have a new tranny now.

[PorscheRacer]

It is possible that the clutches may not be releasing fully and this could be the issue but if that were the case, it would grind in EVERY gear since the rotational speed of the clutches at redline is 8400 RPM regardless of gear.

Therefore, I say it is NOT in the clutch if it only occurs at the 1-2 shift.

I think the issue is simply that 8400 RPM is alot for a synchro to handle and the design of the gearbox makes the 1-2 shift naturally "notchy" for whatever reason.

This to me is the single worst aspect of the M3 manual. The 1-2 shift is ALWAYS notchy and can grind if you shift it quickly.

I don't know if redline oils would help or not. I fear changing it for warranty concerns just like everyone else. I might step up and go first when my tools get moved out here next month if no one else has tried it already.

Right now I'm of the theory that the warranty is there for things like this and if it grinds it grinds. I do shift it much more deliberately to avoid it (than my other cars) but it really sucks that such an action is necessary on a car like this.

[chris719]

This is a common problem in BMW transmissions it seems. I have a similar issue with my Z4M, but it actually only happens below 5k RPM if I try to shift extremely fast. It may do it at 8000, but I don't try to shift hard from first to second at redline every day.

[oneginee]

Originally Posted by PorscheRacer

First, the M3 does have a dual disc clutch. It DOES NOT have a dual mass flywheel.
:

There is nothing wrong with NOT knowing your car. However then don't post things like this it will avoid you some embarassment because you WILL get schooled by someone on this forum. The M3 self adjusting clutch HAS a dual mass flywheel AND a double disc.

Originally Posted by PorscheRacer

It is possible that the clutches may not be releasing fully and this could be the issue but if that were the case, it would grind in EVERY gear since the rotational speed of the clutches at redline is 8400 RPM regardless of gear.

Therefore, I say it is NOT in the clutch if it only occurs at the 1-2 shift.

I think the issue is simply that 8400 RPM is alot for a synchro to handle and the design of the gearbox makes the 1-2 shift naturally "notchy" for whatever reason.

This to me is the single worst aspect of the M3 manual. The 1-2 shift is ALWAYS notchy and can grind if you shift it quickly. :

Again. The rotational speed of the clutch discs is the engine RPM but your reasoning is wrong. 1-2 will has the largest relative difference in rotational speed than any other sequential gear change. therefore it is the most likely to grind at the synchromesh.

[PorscheRacer]

Originally Posted by oneginee

There is nothing wrong with NOT knowing your car. However then don't post things like this it will avoid you some embarassment because you WILL get schooled by someone on this forum. The M3 self adjusting clutch HAS a dual mass flywheel AND a double disc.

Again. The rotational speed of the clutch discs is the engine RPM but your reasoning is wrong. 1-2 will has the largest relative difference in rotational speed than any other sequential gear change. therefore it is the most likely to grind at the synchromesh.

I stand corrected (but not embarrassed ) if the M3 has a dual mass flywheel. I was under the impression it didn't but I think we can both agree that the flywheel has nothing to do with this issue (other than possibly added weight of rotational elements in the clutch).

The way I read your response is that you agree with me now that the problem is not in the clutch "sticking" but in the differential speed of the gear change and therefore in the transmission itself; i.e. the synchro doesn't have the ability to synchronize input shaft speed to 2nd gear speed as quickly as the shift is occurring.

I'll say again, if it was a clutch issue, it would grind in every gear at high RPM because the input shaft speed is the same as engine speed regardless of gear choice which means the clutch speed is the same as engine speed regardless of gear choice.

[MMMorish]

So let me get this straight, the tranny itself was designed with this flaw in 2nd gear? If so, then my replacement tranny won't fix the problem?

Well, then why is it that most of the problems seems to be coming from 08 cars and not 09's?

[PorscheRacer]

These are theories of what is wrong. None of us can say for sure what the issue is but it certainly sounds like a synchro issue in the transmission having to deal with very high engine RPM and large ratio differential gear to gear.

Perhaps the 09 has a change that improves this condition. I hope you'll post when your trans is replaced and let us all know if a problem was found and whether the new 09 trans fixed it.

[MMMorish]

I wonder why John from UUC, when at BMW, got his tranny and supporting components (clutch, flywheel, clutch spring ect..) changed and my dealer will only do the tranny. Should I be pushing them to perhaps do the clutch, flywheel and clutch spring as well?

[PorscheRacer]

Personally, I would say yes, it would be a good idea to change the clutch components. It is almost a case of "while you are in there." I might even be willing to pay the dealer's cost if they won't cover it under warranty to get a new clutch but that would depend on the mileage.

[EDELWEISS]

I got the same damn problem with the grind from 1st to 2nd , thought i was the olny one havnt been here for a while , definitly a problem , never happened with any Porsche BMW or Audi I have ever driven i think the problem is inherint to the 08 M3 , I reoprted this to the dealer , but they couldnt find a problem . I guess I have to take the Tech for a ride.

[MMMorish]

Originally Posted by EDELWEISS

I got the same damn problem with the grind from 1st to 2nd , thought i was the olny one havnt been here for a while , definitly a problem , never happened with any Porsche BMW or Audi I have ever driven i think the problem is inherint to the 08 M3 , I reoprted this to the dealer , but they couldnt find a problem . I guess I have to take the Tech for a ride.

Make sure you're driving the car when you go for a drive with the tech. I'm sure you can make it happen because you know how you're shifting when it does.

[DevJ]

I'm gonna install a ssk Saturday and see if this still happens. I'll keep yall updated.

[rd4LLe92m3]

i had this same problem as well and i let my friend who has very experienced race driver and i did not tell him about it purposely to see if it would happen to him and sure enough there was a grind. Now when i shift even with a pause at high rpms it will grind once i am actually in the gear.

[J08M3]

Originally Posted by DevJ

I'm gonna install a ssk Saturday and see if this still happens. I'll keep yall updated.

doesn't make a difference.... I still get a grind once in awhile from 1-2 with a ssk. Although less often as it feels my shifts are much more precise with the ssk. But the less often might have more to do with me adapting my driving style and purposely slowing down the 1-2 shift to make sure the grind doesn't happen......