Clutch slip or Traction control?

[OneM]

Wondering if anyone has experience this:

Coasting along in 6th gear then downshifting to 4th and giving it some gas. The car doesn't accelerate/pull as normal, its more like the engine rpm rises but the car is not going. It feels as though it isn't in gear. You hear the engine spinning and see the rpm's rise but the car feels like its been de-clutched and doesn't shoot off violently like it should. This even happened to me in 1st gear taking off at the lights.

Could this be the traction control taking over or do you think its more like clutch slip? My car's only 6 months old so I don't think its the clutch. My CDV has been removed by the way.

Any ideas..

Thanks

[alphagamma]

Originally Posted by OneM

Wondering if anyone has experience this:

Coasting along in 6th gear then downshifting to 4th and giving it some gas. The car doesn't accelerate/pull as normal, its more like the engine rpm rises but the car is not going. It feels as though it isn't in gear. You hear the engine spinning and see the rpm's rise but the car feels like its been de-clutched and doesn't shoot off violently like it should. This even happened to me in 1st gear taking off at the lights.

Could this be the traction control taking over or do you think its more like clutch slip? My car's only 6 months old so I don't think its the clutch. My CDV has been removed by the way.

Any ideas..

Thanks

Sounds more like your clutch is going. Traction control usually cuts power, not let the engine spin freely.

[Dackelone]

Sounds like your clutch is slipping. Try turning off your DTC fully by holding down the DTC/DSC for five seconds. Then test it. But be careful!

[Artemis]

Easy test: keep all safety nannies on and check if the yellow DSC light quickly flashes when this phenomenon occurs.

If the DSC light does not flash, it's likely that the clutch starts to slip.

I remember a Belgian guy testing one of the first 1M loaners last year. He reported that the clutch was already slipping despite the car having clocked only a few K kms. Test drive = putting to the test what the car is capable of. Decent car journalists do not perform wild stuff with a loaner (cold engine, brakes, shifting, etc.), so the story goes.

Small question: did you install a so-called "clutch stop" in your 1M (small device allowing you not to push the clutch to maximum position: see http://www.1addicts.com/forums/showthread.php?t=602966 - http://www.clutchstopper.com/index.html - http://www.ebay.com/itm/ws/eBayISAPI...E:L:OC:US:1123) ?

If you got a clutch stop, or you have the driving habit not to push the clutch till its maximum position, and the clutch has to be replaced, then that might be the cause.

[OneM]

Thanks for the replies guys.

Artemis: no I don't have a clutch stop installed. Only CDV delete.

Forgot to mention though.. the slippage only occurs under high rpm or torque load. If I gently take off under wide-open throttle, there's no slippage, only when its an aggressive high rpm take-off or downshifts.

[Artemis]

Other question: ever had a (very) bad gear shift (unhealthy rattling/grinding noise and shuddering gear shift lever, because the gear shift lever was not correctly shifted in the right gear) ? It's quite unlikely that you (or another driver) managed to break one or more "teeth" of the wheel(s), but never say never when the 1M is shifted at hard pace. Although wheel "teeth" are strong, not properly matching wheels should be avoided, of course.



Also check the following thread for additional possibilities (coils, plugs, bad fuel, etc.): http://www.1addicts.com/forums/showt...php?p=12324080. It features the following good piece of advice:

Originally Posted by fastauto

What is your hesitation of simply bringing it to the dealer? Act dumb, say you don't know what the deal is and tell them it better be covered under warranty.

[OneM]

Artemis: no, never had a bad shift so far, no grinding/rattling either..

Fastauto: .. bring it to the dealer. Well, that's my last resort coz 100% of the time while driving hard or normal its fine, no slippage. Only during 'M' mode when I dump the clutch on high rpm's (i.e..high load, say 3-4000rpms) does the slippage occur. So I just wanted to find out if it was normal.

[DarthColin]

If this is what is happening if you dump the clutch, I would suggest clutch slippage is the problem, yuk yuk yuk:

[Dackelone]

Originally Posted by Artemis

Other question: ever had a (very) bad gear shift (unhealthy rattling/grinding noise and shuddering gear shift lever, because the gear shift lever was not correctly shifted in the right gear) ? It's quite unlikely that you (or another driver) managed to break one or more "teeth" of the wheel(s), but never say never when the 1M is shifted at hard pace. Although wheel "teeth" are strong, not properly matching wheels should be avoided, of course.

This is ANOTHER reason why it is a good idea to change one's trans oil often. ALl it takes is for that "chipped" gear tooth to float around and get SMASHED by two gears. Then its bye bye gear.(sooner or later).

Its why synchro's are made from brass - bc they will get worn or chipped over time/hard use.. but when those synchro bits float around the trans oil... when they get smashed by two gear sets... they flatten out and don't damage the gears. Metal gear teeth WILL damage gear(sets).

So... change that trans oil often!

[Artemis]

How clutches work:

01:53 video:


01:16 video:

[OrangeCrush]

Originally Posted by Dackelone

This is ANOTHER reason why it is a good idea to change one's trans oil often. ALl it takes is for that "chipped" gear tooth to float around and get SMASHED by two gears. Then its bye bye gear.(sooner or later).

Its why synchro's are made from brass - bc they will get worn or chipped over time/hard use.. but when those synchro bits float around the trans oil... when they get smashed by two gear sets... they flatten out and don't damage the gears. Metal gear teeth WILL damage gear(sets).

So... change that trans oil often!

Hey Dack! How often do you recommend changing the transition fluid?

[Em/1]

Originally Posted by Dackelone

This is ANOTHER reason why it is a good idea to change one's trans oil often. ALl it takes is for that "chipped" gear tooth to float around and get SMASHED by two gears. Then its bye bye gear.(sooner or later).

Its why synchro's are made from brass - bc they will get worn or chipped over time/hard use.. but when those synchro bits float around the trans oil... when they get smashed by two gear sets... they flatten out and don't damage the gears. Metal gear teeth WILL damage gear(sets).

So... change that trans oil often!

Not to be a pain in the ass, but brass IS a metal alloy, just a "soft" one...

[Dackelone]

Originally Posted by OrangeCrush

Hey Dack! How often do you recommend changing the transition fluid?

Inthe old days BMW said every 30K miles. I would change at every 30K at a min. Maybe more often ~20K miles.

For the M cars, BMW says every THIRD oil change, to change the diff and trans oil.

[Dackelone]

Originally Posted by Em/1

Not to be a pain in the ass, but brass IS a metal alloy, just a "soft" one...

Yes, the brass is soft so when a broken bit of brass gets smashed between two gear sets... nothing bad happens. IF a piece of harden metal gear gets smashed between two gears, it is not good.

Ever hear people grinding reverse gear, when they are selecting reverse gear on a (cheap/eco-box)manual car. When you get that grinding noise... it is not good. Ever hear people speed up in reverse and let off the gas... the trans makes a funny gear type noise... with some ticking sounds... most of that is due to gears that are damaged from broken teeth.

I think it is why BMW has used a synchronized reverse gear for years & years. On VW's for instance... they still do not have a synchronized reverse gear!

[OneM]

I think I figured it out.. now I know why BMW chose to install the CDV (clutch delay valve), which I removed on my car. It's there not just to prevent shocks to the drivetrain, but also in my case where high load/rpm launches occurs, it helps delay or slow down the clutch engagement and thus prevent slip.

Make sense to me but I could be wrong.

[bmw1racer]

Originally Posted by OrangeCrush

Hey Dack! How often do you recommend changing the transition fluid?

Transition fluid?

[MDORPHN]

Originally Posted by bmw1racer

Transition fluid?

Yes, it comes into play when you're transitioning from one gear to another

Neil

[silvs]

Originally Posted by OneM

I think I figured it out.. now I know why BMW chose to install the CDV (clutch delay valve), which I removed on my car. It's there not just to prevent shocks to the drivetrain, but also in my case where high load/rpm launches occurs, it helps delay or slow down the clutch engagement and thus prevent slip.

Make sense to me but I could be wrong.

Why are you dropping the clutch? You had posted about this earlier as well.

[bmw1racer]

Originally Posted by MDORPHN

Yes, it comes into play when you're transitioning from one gear to another

Neil

Ah, must be a slushbox thing.

[OrangeCrush]

Originally Posted by bmw1racer

Transition fluid?

Originally Posted by MDORPHN

Yes, it comes into play when you're transitioning from one gear to another

Neil

Ok Ok....stupid phone

[Artemis]

Originally Posted by OrangeCrush

Hey Dack! How often do you recommend changing the transition fluid?

Bea///M me up, Scotty !

[G2G]

Originally Posted by OneM

Wondering if anyone has experience this:

Coasting along in 6th gear then downshifting to 4th and giving it some gas. The car doesn't accelerate/pull as normal, its more like the engine rpm rises but the car is not going. It feels as though it isn't in gear. You hear the engine spinning and see the rpm's rise but the car feels like its been de-clutched and doesn't shoot off violently like it should. This even happened to me in 1st gear taking off at the lights.

Could this be the traction control taking over or do you think its more like clutch slip? My car's only 6 months old so I don't think its the clutch. My CDV has been removed by the way.

Any ideas..

Thanks

hey,
I´m currently experiencing the exact same problem since today!
I talked to service person from the hotline he also said its likely that it is the clutch!
How did it turn out with your 1M?

Cheers