CDV delete question

///1M · 08-28-2014, 02:24 PM

Will a CDV delete make the "clunk" go away between 1-2?

MDORPHN · 08-28-2014, 02:28 PM

Quote:

Originally Posted by ///1M

Will a CDV delete make the "clunk" go away between 1-2?

There shouldn't be a "clunk" with or without the CDV...

Neil

dcaron9999 · 08-28-2014, 02:29 PM

Might not totally eliminate the clunk, but will help with much faster clutch engagement and disengagement.

Looks like you are due for a transmission fluid replacement.

Extremely easy to do.

Just use a good quality ATF such as Redline D4-ATF.
Confirm whether you need D4 or D6 fluid with their online "application guide".

I track my 6-speed manual N55 135i which has the same tranny as in your 1M. Ive changed my tranny fluid twice this year as it wears down after hard use on the track, and shifting becomes "notchy".

///1M · 08-28-2014, 04:52 PM

Thanks dcaron! I've made an appointment for Saturday to have the transmission fluid replaced with Redline D6 ATF.

I'm also having the differential fluid replaced with the standard BMW stuff.

MightyMouseTech · 08-28-2014, 05:20 PM

I would recommend the MTL, I prefer it over the D4 which I found notchy.

MDORPHN · 08-28-2014, 06:22 PM

I may have misunderstood what you described as a clunk.

Are you referring to a mechanical sound/jolt from the clutch/tranny or a notchy feel in the shift lever?

Neil

david.orr · 08-28-2014, 08:18 PM

Or feels like a clump on engagement? Irrespective, CDV delete is a no brainer and you may kick yourself afterwards for not doing it earlier!

///1M · 08-28-2014, 08:34 PM

Quote:

Originally Posted by MDORPHN

I may have misunderstood what you described as a clunk.

Are you referring to a mechanical sound/jolt from the clutch/tranny or a notchy feel in the shift lever?

Neil

Hey Neil,

It's a mechanical jolt from the transmission when I depress the clutch going from 1-2. Usually when the car is still cold. I haven't noticed a major problem in the shift lever.

Pat

IEDEI · 08-28-2014, 08:35 PM

do you guys think doing a CDV delete will wear out the clutch quicker? what is the relationship to the CDV and wearing out of the clutch? I've been thinking of doing it....although i have to say i am mostly pretty damn satisfied with the gearbox so i'm wondering if i shouldn't mess with it if i already dig it so much.

i DO get the clunk occasionally from 1st to 2nd though....i've just learned to accept it. lol.

///1M · 08-28-2014, 08:37 PM

Quote:

Originally Posted by MightyMouseTech

I would recommend the MTL, I prefer it over the D4 which I found notchy.

Mighty Mouse, do you mean Redline's manual transmission fluid, or BMW's?

Harlequin · 08-28-2014, 08:46 PM

Quote:

Originally Posted by IEDEI

do you guys think doing a CDV delete will wear out the clutch quicker? what is the relationship to the CDV and wearing out of the clutch? I've been thinking of doing it....although i have to say i am mostly pretty damn satisfied with the gearbox so i'm wondering if i shouldn't mess with it if i already dig it so much.

i DO get the clunk occasionally from 1st to 2nd though....i've just learned to accept it. lol.

If you're good with a manual gearbox then the CDV is actually better for the clutch. The Delay Valve is there to protect the car from people who shouldn't be driving stick in the first place...

And you won't believe the difference it makes. Best mod you can do.

IEDEI · 08-28-2014, 08:57 PM

Quote:

Originally Posted by Harlequin

If you're good with a manual gearbox then the CDV is actually better for the clutch. The Delay Valve is there to protect the car from people who shouldn't be driving stick in the first place...

And you won't believe the difference it makes. Best mod you can do.

that much huh? i guess i'll have it done soon...thanks, man!

Em/1 · 08-28-2014, 09:16 PM

Quote:

Originally Posted by Harlequin

If you're good with a manual gearbox then the CDV is actually better for the clutch. The Delay Valve is there to protect the car from people who shouldn't be driving stick in the first place...

And you won't believe the difference it makes. Best mod you can do.

I think you meant CDV DELETE is better for the clutch...

MightyMouseTech · 08-29-2014, 08:34 AM

Quote:

Originally Posted by ///1M

Quote:

Originally Posted by MightyMouseTech

I would recommend the MTL, I prefer it over the D4 which I found notchy.

Mighty Mouse, do you mean Redline's manual transmission fluid, or BMW's?

Redline MTL

Found my tranny notchy when new. Flushed with factory MTF-LT-5, same, flushed with Redline D4, better, but still notchy. Switched to the Redline MTL, much better.

Harlequin · 08-29-2014, 08:43 AM

Quote:

Originally Posted by Em/1

I think you meant CDV DELETE is better for the clutch...

Yep. Typed it in a hurry...

All good though. I think IEDEI still got the gist of my post

JeffyD · 08-29-2014, 10:47 AM

The clunk from first to second is due to improperly timing clutch and throttle inputs. I was having an issue with it in my 1M until a buddy of mine gave me a quick in-depth tutorial on what I was doing to cause it.

If such a case is shared between you and I, I'll say that the clunk, for me at least, was remedied by simply being more mindful of where the clutch engaged, and trimming up some sloppy left foot work on my part. And coordinating that with a more precise, and gentler throttle input. Which was made a lot easier for me by simply learning with the sport mapping on - making the shift a smooth process with normal mapping was no issue at all afterwards.

My M coupe made me terrified of the clunk noise - every time I heard it, back when I was learning standard, I was certain my subframe had revolted from my car. Which it probably did.

///1M · 08-29-2014, 05:28 PM

Quote:

Originally Posted by MightyMouseTech

I would recommend the MTL, I prefer it over the D4 which I found notchy.

I bought a gallon of the MTL. I'm due to have it put in tomorrow. Does anyone know if I will potentially damage the gears with this stuff?

ayao · 08-29-2014, 05:33 PM

Just to muddy the waters a little more...

http://www.1addicts.com/forums/showthread.php?t=765175

///1M · 08-29-2014, 06:29 PM

Quote:

Originally Posted by ayao

Just to muddy the waters a little more...

http://www.1addicts.com/forums/showthread.php?t=765175

Indeed that does muddy the waters! Now I'm leaning towards BMW MTF LT-6, which has apparently superseded the LT-5!

At least this will flush it out and get some fresh oil in there.

I'll post an update this weekend.

blotto649 · 08-31-2014, 11:04 AM

I just replaced my tranny and diff fluid at 30,000km on a fairly heavily tracked car.
Shifts have become more and more notchy with the mileage creeping up, so I replaced with BMW LT-5 as per factory spec. Fluid that came out looked very clean and new fluid hasn't done anything to improve shifter feel. I will consider Redline next time around.

Diff fluid was also replaced with factory spec fluid with the FM additive. Old fluid was surprisingly dark and cloudy considering it had already been flushed after break-in. I will continue to change that annually.

Here are my mostly uneducated feelings on the clunk the OP was referring to. When shifting in lower gears, there is a pronounced noise that comes from what I think is the diff when abruptly letting off throttle, either to decelerate or to clutch in and make a shift. Depending on driving style, there may be a point where you completely let off throttle before disengaging the clutch, and I think it's the abrupt change in force on the diff that creates that noise. With slightly different timing between going off-throttle and disengaging the clutch (i.e.. disengaging clutch a little later while still coming off throttle), that change in force can be circumvented and you won't hear the noise. Hard to say if it's bad for the diff to undergo that abrupt change - I just try to be a little smoother when coming off the throttle. Pretty much what I think JeffyD was referring to.

08-28-2014, 02:24 PM	#1
///1M Captain 25 Rep 612 Posts Drives: On a good day, AW 1M coupe Join Date: Mar 2011 Location: between Indiana and the alley iTrader: (0)	CDV delete question Will a CDV delete make the "clunk" go away between 1-2?
	Appreciate 0 Tweet Quote

08-28-2014, 02:29 PM	#3
dcaron9999 Major 157 Rep 1,409 Posts Drives: 2011 135i M package Join Date: Jan 2010 Location: Mirabel, Quebec iTrader: (0)	Might not totally eliminate the clunk, but will help with much faster clutch engagement and disengagement. Looks like you are due for a transmission fluid replacement. Extremely easy to do. Just use a good quality ATF such as Redline D4-ATF. Confirm whether you need D4 or D6 fluid with their online "application guide". I track my 6-speed manual N55 135i which has the same tranny as in your 1M. Ive changed my tranny fluid twice this year as it wears down after hard use on the track, and shifting becomes "notchy". __________________ 2011 X3 35i with M pack + 2011 135i w/6SPMT \| 255 square tire setup \| Quaife 3.46 LSD \| Diff lock down bracket \| Bilstein B8+Swift SpecR springs+H&R FSB \| CDV delete \| BMS Oil Tstat bypass \| ER FMIC & CP \| N54Tuning DP \| GC Street Camber Plates \| M3 FCA +guide rods+RSFB's+Tranny mounts \| Manzo toe arms \| Cobb Stg2 agressive tune \| Hawk DTC70 brake pads \| RB SS brake pistons \| Goodridge SS brake lines \| Custom brake cooling ducts
	Appreciate 0 Quote

08-28-2014, 04:52 PM	#4
///1M Captain 25 Rep 612 Posts Drives: On a good day, AW 1M coupe Join Date: Mar 2011 Location: between Indiana and the alley iTrader: (0)	Thanks dcaron! I've made an appointment for Saturday to have the transmission fluid replaced with Redline D6 ATF. I'm also having the differential fluid replaced with the standard BMW stuff.
	Appreciate 0 Quote

08-28-2014, 05:20 PM	#5
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	I would recommend the MTL, I prefer it over the D4 which I found notchy.
	Appreciate 0 Quote

08-28-2014, 06:22 PM	#6
MDORPHN Colonel 291 Rep 2,898 Posts Drives: AW 1M Join Date: Oct 2010 Location: Wash, DC iTrader: (0)	I may have misunderstood what you described as a clunk. Are you referring to a mechanical sound/jolt from the clutch/tranny or a notchy feel in the shift lever? Neil
	Appreciate 0 Quote

08-28-2014, 08:18 PM	#7
david.orr Lieutenant Colonel 123 Rep 1,852 Posts Drives: Cars Join Date: Aug 2011 Location: Australia iTrader: (0)	Or feels like a clump on engagement? Irrespective, CDV delete is a no brainer and you may kick yourself afterwards for not doing it earlier!
	Appreciate 0 Quote

08-28-2014, 08:35 PM	#9
IEDEI Banned 1130 Rep 4,686 Posts Drives: L'Orange Join Date: Jul 2013 Location: Brooklyn, NYC iTrader: (0) Garage List 2011 BMW 1M [8.40]	do you guys think doing a CDV delete will wear out the clutch quicker? what is the relationship to the CDV and wearing out of the clutch? I've been thinking of doing it....although i have to say i am mostly pretty damn satisfied with the gearbox so i'm wondering if i shouldn't mess with it if i already dig it so much. i DO get the clunk occasionally from 1st to 2nd though....i've just learned to accept it. lol.
	Appreciate 0 Quote

08-29-2014, 10:47 AM	#16
JeffyD Destroy All Monsters 3 Rep 159 Posts Drives: '02 EB M Coupe, '11 M Coupe Join Date: Feb 2014 Location: Southern California iTrader: (0)	The clunk from first to second is due to improperly timing clutch and throttle inputs. I was having an issue with it in my 1M until a buddy of mine gave me a quick in-depth tutorial on what I was doing to cause it. If such a case is shared between you and I, I'll say that the clunk, for me at least, was remedied by simply being more mindful of where the clutch engaged, and trimming up some sloppy left foot work on my part. And coordinating that with a more precise, and gentler throttle input. Which was made a lot easier for me by simply learning with the sport mapping on - making the shift a smooth process with normal mapping was no issue at all afterwards. My M coupe made me terrified of the clunk noise - every time I heard it, back when I was learning standard, I was certain my subframe had revolted from my car. Which it probably did.
	Appreciate 0 Quote

08-29-2014, 05:33 PM	#18
ayao Thread killer 642 Rep 1,896 Posts Drives: 1M Join Date: Aug 2011 Location: CA iTrader: (2)	Just to muddy the waters a little more... http://www.1addicts.com/forums/showthread.php?t=765175
	Appreciate 0 Quote

08-31-2014, 11:04 AM	#20
blotto649 Private First Class 16 Rep 137 Posts Drives: '04 996 GT3/'88 911 Carrera Join Date: Nov 2010 Location: Between Toronto and Ottawa iTrader: (0)	I just replaced my tranny and diff fluid at 30,000km on a fairly heavily tracked car. Shifts have become more and more notchy with the mileage creeping up, so I replaced with BMW LT-5 as per factory spec. Fluid that came out looked very clean and new fluid hasn't done anything to improve shifter feel. I will consider Redline next time around. Diff fluid was also replaced with factory spec fluid with the FM additive. Old fluid was surprisingly dark and cloudy considering it had already been flushed after break-in. I will continue to change that annually. Here are my mostly uneducated feelings on the clunk the OP was referring to. When shifting in lower gears, there is a pronounced noise that comes from what I think is the diff when abruptly letting off throttle, either to decelerate or to clutch in and make a shift. Depending on driving style, there may be a point where you completely let off throttle before disengaging the clutch, and I think it's the abrupt change in force on the diff that creates that noise. With slightly different timing between going off-throttle and disengaging the clutch (i.e.. disengaging clutch a little later while still coming off throttle), that change in force can be circumvented and you won't hear the noise. Hard to say if it's bad for the diff to undergo that abrupt change - I just try to be a little smoother when coming off the throttle. Pretty much what I think JeffyD was referring to.
	Appreciate 0 Quote