BMW M5 Forum and M6 Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Hi everyone,

).<?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:)) be an electronic problem?
<o:p></o:p>
<o:p></o:p>
Any advice or feedback is welcome!<o:p></o:p>
 

·
Registered
Joined
·
5 Posts
Discussion Starter #2
Looks like I have messed up my post -sorry for that
-------
Hi everyone,

I have read a lot about E60 M5 clutch problems on this forum, although haven’t found any post corresponding to the one I am experiencing, so I created a new post. I own a 2008 M5, EU specs 80’000 km, spirited driving – rear tyres ARE consumable. Never used the launch control. Very happy about the car (although 200HP short or 500KG too heavy).

For a few month now, there is something slipping when I accelerate. This happens essentially in gear 4 to 7, above 3k rpm. It’s like a quick declutch, letting the engine taking about 500 rpm while the car accelerates a little, then gripping again for a full acceleration. The symptom is the same in p400 and p500 mode, with or without the TC. I’d tend to think the clutch is dying, although when fully accelerating in gear 1-2-3, I “seem” to get full power and full traction and don’t really feel such slippage even flat out on P500. I’d expect to get rather more slippage in lower gears where the transmission is in principle getting harder punishment if it was the clutch.

I have no error message, the only issue I recently had was with a lambda probe, that I just had replaced. I have re-calibrated the clutch several times. I don’t see any difference if engine is cold or at temperature. It doesn’t smell anything but rubber after a hard drive.
So the questions is, has someone ever experienced similar behaviour? If so was this diagnosed as a failing clutch? Could this possibly (hopefully) be an electronic problem?

Any advice or feedback is welcome!
 

·
Registered
Joined
·
79 Posts
I had similar symtoms and clutch was covered in oil from bad rear main seal. Weird how it would never slip in lower gears only high ones and only around 4k rpm. Make sure when u do new clutch to change rear main and pilot bearing and the two seals in the transmission side (input shaft and blank cover just below) as well. With trans out consider putting in new slave cyl since u can only replace it with trans out.

Definately will need a new clutch and they recommend replacing the flywheel at same time. There are min two special tools u will need so do a search.


Sent from AutoGuide.com Free App
 

·
Registered
Joined
·
5 Posts
Discussion Starter #4
Thanks Funbobbyrob,
I had read about the leaking seals although did not realise the symptoms were the same. This is strange how it only slips at this rate.
Anyway, thanks for the advice, I have also read about replacing the slave cylinder and flywheel simultaneously with transmission, as well as bearings and seals, but I will have it done in a garage – a bit too complex for me. I am looking at what parts are available in Switzerland at decent price, likely considering the Sachs OEM kit.
 

·
Registered
Joined
·
368 Posts
I don't have experience with the SMG, but the clutch portion is pretty standard.

A slipping clutch will begin to slip in the higher gears first and when the engine begins to make torque/power...ie on the highway under heavy load.

Once it begins slipping it 'won't' catch up...it just slips. Example, my other car recently did this after 165,000 miles...step on the gas hard in 4th and the engine rpm increased with little increase in speed...and it just kept zinging to redline if I stayed in it.

If yours is slipping and then "hooks up", I would expect something on the actuation side-not a failed clutch disk/cover.

Actually haven't read too many failed clutches due to slipping on this forum.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #6 (Edited)
Thanks Tim Mc,<?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com<img src=" /><o:p></o:p>
The slipping behaviour you described is what I’d expect indeed. If the clutch is hooking up again, it means the slippage is detected and the takes an action. It’s either reducing the torque e.g. by reducing the power (although I’d assume I’d perceive it) or that the clutch’s grip is somehow “reinforced” although I don’t think this is an M5 feature.<o:p></o:p>
<o:p></o:p>
This is why I was also suspecting an electronic problem. Any interaction possible with the faulty lambda probe (such as unburned gas detected) that may alter the measure of the torque, leading to order RPM increase by a brief declutch?<o:p></o:p>
<o:p></o:p>
On the clutch actuator side, I assume that if faulty, you have to dismount the clutch to reach it, thus better replace it anyway right?<o:p></o:p>
 

·
Registered
Joined
·
5 Posts
Discussion Starter #7
All right, so I got an explanation from a friend who’s a former mechanic at BMW. There is a sensor used to detect clutch position. With clutch wearing, the sensor position becomes off limit, which leads to command brief declutch at certain RPM. So the clutch is indeed dying but is still able to cope with full torque, this is why it can support full power acceleration but slips at certain revs on medium ones.
 

·
Registered
Joined
·
33 Posts
Your clutch is dying. I had the EXACT same situation as you. It started slipping in 4th gear. But under 1,2,3 full acceleration from a dead stop was fine.

But only difference was after slippage in 4th, it threw a real quick yellow cog and would disappear. Yellow cog never stayed on.
 
1 - 8 of 8 Posts
Top