Clutch not engaging while driving.

[Bealo]

Interesting. Did you perform the SMG -> tyre recalibration? Like you should when you change tyres (see the handbook section on changing tyres).
If you don't it can throw the SMG into a bit of a wobbly.

It's what's often referred to as the 'SMG reset' (car into N or 0 at 40mph, pull & hold both paddles for about 4 or 5 seconds then back into gear).

I never knew that, I never did the SMG reset when i changed from 265 rears to 275 rears.

I'm about to put some cups on my car so i will do the reset just to be on the safe side.

hope you find out what the problem is soon bryce. :thumbs:

[mattbedford]

How do you get it into neutral at 40mph?

[glendog74]

How do you get it into neutral at 40mph?

Push the gear selector 'stick' to the left

[bryce]

So it only does it in a down hill situation and not uphill and not when on flat ground? And only with part throttle??

Ermm, downhill mostly I think (Its one of them things though, hard to repeat when trying!) And yes, only on part throttle.

I have noticed if I downshift, (4th - 3rd) there's a delay before the clutch comes back in. Its as if its missed the gear. This is when free wheeling and not braking.

Doing my nut in :banghead:

[NZ_M3]

I have noticed if I downshift, (4th - 3rd) there's a delay before the clutch comes back in. Its as if its missed the gear. This is when free wheeling and not braking.

I had exactly this in my car before - except it was almost all gears, worse on the lower gear downshifts.

It turned out to be a faulty release bearing.

Our release bearing sits on a plastic sleeve on the input shaft - the design of the clutch slave cylinder and fork is such that it pushes only on one side of the fork - overtime the inner edges of the release bearing and the plastic sleeve gets worn out inconsistently left to right - causing it to catch on release. There's an aftermarket sleeve that you can buy that's made of an alloy of some sort that prevents this from happening.

I am suspecting that you might have what I had happen with my release bearing - completely worn on one side and almost non on the other, causing it to intermittently catch on release - i.e. the delay you feel on downshifts and sometimes upshift.

Lucky for me it was warranty work - free clutch kit and labour!!


Of course your situation might not be the same as mine - it could be a purely gearbox issue - the sensors might be sensing that it's hard to engage gear, thus dropping the clutch and putting it back into neutral before trying again - this happens when the synchronmesh is worn out or about to wear out. It should however register in the DME that it's had trouble engaging gears though.

Might pay to flush out that gearbox fluid and put in some new fluids and see if it helps - might even be a low fluid situation, who knows?

[bryce]

I had exactly this in my car before - except it was almost all gears, worse on the lower gear downshifts.

Thank you again. I always enjoy reading your posts as they're very informative :thumbs:

Well I was out last night for a spin, and it seems to be getting worse. Not always similar symtoms to what I described though. New ones are:

Changing up/down gear, the revs are wobbling as if it cant find the gear.
In gear (mostly third/fourth) at cruise throttle, and apply an extra half throttle I get a 'thud - thud' noise and it jolts the whole car (feeling from the rear). Again, as if the clutch wasnt in right, it takes two quick goes at re-engaging, and away we go.

What ya reckon Richie?

[bryce]

First time the 'Register has been stuck for a remedie...? :banghead:

[Mark CSL]

Bring it up and let my mtec mate have a go :thumbs:

[NZ_M3]

Thank you again. I always enjoy reading your posts as they're very informative :thumbs:

Well I was out last night for a spin, and it seems to be getting worse. Not always similar symtoms to what I described though. New ones are:

Changing up/down gear, the revs are wobbling as if it cant find the gear.
In gear (mostly third/fourth) at cruise throttle, and apply an extra half throttle I get a 'thud - thud' noise and it jolts the whole car (feeling from the rear). Again, as if the clutch wasnt in right, it takes two quick goes at re-engaging, and away we go.

What ya reckon Richie?

I am beginning to think that it's mechanical to be honest - might be a new gearbox time for you.

[bryce]

I am beginning to think that it's mechanical to be honest - might be a new gearbox time for you.

Uh oh :banghead: Just as well Ive extended the warranty.

How do I go about getting them to do the gearbox though? Ive already had them have a look at it, but they only checked oil levels, pressures and all sensors.

As always, it'll not do 'it' when I take the car in :banghead:

[NZ_M3]

I'd ask them to re-teach the clutch and reprogram the SMG shifts (2 separate things) and see if that corrects the problem.

If it's hesitating to get into gear it's does sound like a mechanical issue more than a programming issue - but you never know.

Another possibility is a bad pressure plate - these cars use a LuK self adjusting pressure plate - and occassionally when the clutch plate is worn it'd 'hunt' for the take up point - if you get the dealer to re-teach the clutch take up point it usually resolves this hunting issue (worth a try) - no fault code will show for this one (when my release bearing craped itself I had the clutch take up point reinitiated three times and SMG retaught twice before BMW finally decided to drop the gearbox to see what was wrong).

Good luck and keep us updated.