M6 gearbox fault

[jcolley]

Slippydiff said:

A BMW technician recently told me that BMW experienced issues with early V10 engined SMG cars when the actuators were moving too quickly to select a gear, ie before the "currently used" actuator had been given time to return to it's "resting/neutral" position. the end result was the two gears being selected (or an attempt to do so) with catastrophic results. Is this possible/true ?

Absolutely possible.

If you look in the technical docs thread on M5Board

http://www.m5board.com/vbulletin/e60-m5-e61-m5-touring-discussion/213154-m5-m6-s85-recall-tech-service-bulletin-service-information-bulletin-technical-docs-thread-one-stop-shop.html

there are several PDFs from BMW with more detail than most people ever wanted. Particularly in the "Complete Vehicle" PDF, a fairly in-depth discussion of the SMG including hydraulic and electrical schematics.

If you look, the transmission was specifically designed to make use of two separate shift rods for each gear change with the exception of 1-R and 6-7. This is because of the control layout, two separate speed adjusting valves are used for the gear change. This allows, for example when shifting from 1-2, for the speed control valve for shift rod 1/R to start motion very quickly to disengage the gear, then slow as as it approaches the mid-point (for neutral), yet keeping the speed control valve for the incoming 2nd gear shift rod (rod 2/4) to remain fully open for maximum engagement speed as soon as the 1/R rod hits the mid-point.

If the mid-point calibrations (performed in step 2, "adapt complete transmission") are incorrect, the gear change will be slower than desired and/or harsh as it tries to engage the incoming gear before the outgoing gear is fully disengaged.

Yes...I've probably spent far too much time staring at that schematic...

Edited by jcolley on Wednesday 12th February 01:56

[jcolley]

jon- said:

jcolley - you're awesome.

Hehe, tell my wife that. She says "great, another forum". I spent a lot of time that could probably have been used better.

[AW10]

Yes, do tell your wife that your forum contributions are appreciated around the world!

Thanks for posting the DIY on M5board and joining us here. My car is nicer to drive after the adaptation. Not that I was thinking of selling it but now I'm more inclined to keep it. I will try a summer adaptation as well for when things here warm up (and dry out).

[Schermerhorn]

How much does the adaption cost?

[jcolley]

Schermerhorn said:

How much does the adaption cost?

It takes about 30 minutes tops including connecting the car to the ICOM, reading out the data (VIN. Vehicle order, and error codes) and navigating to the test procedure and running it. Most dealerships or shops probably don't charge by the half-hour, so I would guess an hour.

Or if you're computer savvy, get a copy of INPA, DIS, or ISTA/D and do it yourself.

[bmwm6bruce]

have just received back finally my M6 from BMW . It has a brand new Gearbox fitted under warranty (thank God) as been told that it would of been £9000 if not . Ouch !!! Picking up on what a Fellow said earlier in this thread , that he also had a new gearbox fitted and it felt jerky and clunky . Well snap so does this one at low speeds , but when you increase speed its just awesome . I can only say that anyone out there doing there homework before buying one of these iconic Cars . You must buy one with a BMW warranty as these can be a very expensive Beast if not . I have been bitten by the V 10 bug . Nothing can prepare you for that first drive , as its love at first drive . Well it was for me . I am very thankfull to BMW Norwich who dealt with this problem in a very professional way . Cant recommend them enough . And the loan car they gave me was very nice 320d M sport touring . Will be using them with out question for future servicing work and if you are local to Norwich suggest you do the same . Anyway now back among the elite again you cant beat a M car !!!!!!

[detchibe]

Hi Bruce, I concur with your thoughts about Cooper Norwich. Previously heard nothing but bad experiences but they seem to have turned things around recently and have been excellent with my 645ci and Mini. Will have to keep an eye out for you as I don't often see any M6's, I now have an Interlagos Blue Z4MR.

[jcolley]

bmwm6bruce said:

have just received back finally my M6 from BMW . It has a brand new Gearbox fitted under warranty (thank God) as been told that it would of been £9000 if not . Ouch !!! Picking up on what a Fellow said earlier in this thread , that he also had a new gearbox fitted and it felt jerky and clunky . Well snap so does this one at low speeds , but when you increase speed its just awesome . I can only say that anyone out there doing there homework before buying one of these iconic Cars . You must buy one with a BMW warranty as these can be a very expensive Beast if not . I have been bitten by the V 10 bug . Nothing can prepare you for that first drive , as its love at first drive . Well it was for me . I am very thankfull to BMW Norwich who dealt with this problem in a very professional way . Cant recommend them enough . And the loan car they gave me was very nice 320d M sport touring . Will be using them with out question for future servicing work and if you are local to Norwich suggest you do the same . Anyway now back among the elite again you cant beat a M car !!!!!!

If the gearbox is new, I'm assuming the clutch is as well. A lot of guys on M5board have reported the SMG is harsh after a clutch replacement and smooths out significantly if re-adapted after 1000 miles or so once the clutch is "bedded" so to speak, much like brakes and rotors.

[junglist]

jcolley said:

bmwm6bruce said:

have just received back finally my M6 from BMW . It has a brand new Gearbox fitted under warranty (thank God) as been told that it would of been £9000 if not . Ouch !!! Picking up on what a Fellow said earlier in this thread , that he also had a new gearbox fitted and it felt jerky and clunky . Well snap so does this one at low speeds , but when you increase speed its just awesome . I can only say that anyone out there doing there homework before buying one of these iconic Cars . You must buy one with a BMW warranty as these can be a very expensive Beast if not . I have been bitten by the V 10 bug . Nothing can prepare you for that first drive , as its love at first drive . Well it was for me . I am very thankfull to BMW Norwich who dealt with this problem in a very professional way . Cant recommend them enough . And the loan car they gave me was very nice 320d M sport touring . Will be using them with out question for future servicing work and if you are local to Norwich suggest you do the same . Anyway now back among the elite again you cant beat a M car !!!!!!

If the gearbox is new, I'm assuming the clutch is as well. A lot of guys on M5board have reported the SMG is harsh after a clutch replacement and smooths out significantly if re-adapted after 1000 miles or so once the clutch is "bedded" so to speak, much like brakes and rotors.

I'm taking mine to a BMW specialist on Friday to have the clutch re-adapted, I've done 2000 miles since the box was replaced in December. I'll report back after the weekend what it's like. Did Norwich BMW suggest you have the SMG oil changed after 1000 miles running in? BMW told me I had to do it on mine, which I have done just to be safe.

[junglist]

jcolley said:

bmwm6bruce said:

have just received back finally my M6 from BMW . It has a brand new Gearbox fitted under warranty (thank God) as been told that it would of been £9000 if not . Ouch !!! Picking up on what a Fellow said earlier in this thread , that he also had a new gearbox fitted and it felt jerky and clunky . Well snap so does this one at low speeds , but when you increase speed its just awesome . I can only say that anyone out there doing there homework before buying one of these iconic Cars . You must buy one with a BMW warranty as these can be a very expensive Beast if not . I have been bitten by the V 10 bug . Nothing can prepare you for that first drive , as its love at first drive . Well it was for me . I am very thankfull to BMW Norwich who dealt with this problem in a very professional way . Cant recommend them enough . And the loan car they gave me was very nice 320d M sport touring . Will be using them with out question for future servicing work and if you are local to Norwich suggest you do the same . Anyway now back among the elite again you cant beat a M car !!!!!!

If the gearbox is new, I'm assuming the clutch is as well. A lot of guys on M5board have reported the SMG is harsh after a clutch replacement and smooths out significantly if re-adapted after 1000 miles or so once the clutch is "bedded" so to speak, much like brakes and rotors.

I'm taking mine to a BMW specialist on Friday to have the clutch re-adapted, I've done 2000 miles since the box was replaced in December. I'll report back after the weekend what it's like. Did Norwich BMW suggest you have the SMG oil changed after 1000 miles running in? BMW told me I had to do it on mine, which I have done just to be safe.

[bmwm6bruce]

Clutch and Flywheel was replaced prior to this visit . there was no mention of transmission fluid change at 1000 miles . So have no idea . Will ask now you have mentioned it .

[bmwm6bruce]

detchibe said:

Hi Bruce, I concur with your thoughts about Cooper Norwich. Previously heard nothing but bad experiences but they seem to have turned things around recently and have been excellent with my 645ci and Mini. Will have to keep an eye out for you as I don't often see any M6's, I now have an Interlagos Blue Z4MR.

I will keep alook out for your Z4M as not seen many of them around either . You will know me as im the bald head man grinning all the time Lol

[junglist]

Clutch now re-adapted by an independant BMW specialist (I specified it to be done with the powertrain/tranmission at operating temperature). I've only done 30 miles since picking it up but there is a marked improvement in the transmission, it still clunks down in to first gear but not as I experienced before. The truth in the pudding will be going from a cold start tomorrow morning...

[bmwm6bruce]

Let us know how the cold start went. As my one may need the same b

[bmwm6bruce]

Let us know how the cold start went. As my one may need the same

[junglist]

So then, it's much more improved when pulling to a stop i.e. the clutch opens much more smoothly to break drive. Gear changes overall are slightly better but I still have regular clunks shifting down 3rd to 2nd to 1st. Sometimes 1st to 2nd upshifts are a bit savage depending on throttle position when requesting the upshift while pulling away

[r spec]

Interesting stuff guys! Jcolley you've taken my worries away :-) Thrown the PLCD errors since I left the car sat for 4 weeks over the holidays - groan!

Anyhow there is another problem which may go away when its replaced but was present for a few thousand miles before any error codes appeared.

This problem presents itself in these ways:
- in D the SMG will not select 2nd gear at standstill
- in D or +/- the SMG refuses to change gear below 3000 rpm
- very occasionally it will be happy to change at 2500 rpm but then quickly reverts to 3000 rpm.

I have a slow traffic journey to work so know full well that I used to change at 1500-1700 rpm all day long...

Assuming this is a limp home or similar calibration change within the SMG controller preventing low rpm gear changes or 2nd gear pull away.

p.s. been waiting for admin approval on the m5board for months. Tried registering with other emails too in case it got lost in the system but even though I can log in I cannot post.

[jcolley]

r spec said:

p.s. been waiting for admin approval on the m5board for months. Tried registering with other emails too in case it got lost in the system but even though I can log in I cannot post.

Under what username? I'll look into it.

[jcolley]

The first thing to do is have the SMG adaptation procedure performed in DIS, INPA, or ISTA/D (all BMW diag software). It may solve problems you perceive or it could fail the procedure which will help identify a mechanical fault.

Aside from that, reading any stored error codes is the only way to chase it down.

[r spec]

Cool thanks. Its thrown 510D and 510E (as well as 4FAO)... So perhaps 4FA0 had come first causing the first downrated performance and then the actual failure came about... So having the PLCD changed soon which must mean my local Indy will run the adaptation afterwards. Hopefully that'll fix it then :-)

Same user name but with '-' i.e. r-spec :-) Thanks!

Edited by r spec on Monday 16th February 10:01