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Clutch Delay Valve?

186K views 424 replies 105 participants last post by  Shocktrooper392 
#1 · (Edited)
I'm installing a new spec clutch as my old OEM is finally going out. We ordered new actuator(slave cylinder) and pilot bearing. On the actuator there appears to be a CDV and my installer mentioned removing it would be a good idea for many reasons and a quick Google search will show you why but it essentially hinder quick shifts and reduces clutch life. Has anyone gone down the road of removing one or coming up with a workaround?
 

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#2 ·
We have one. I removed it.
 

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#4 ·
Correct. Slows the disengagement of the clutch. So even under normal use it makes the separation slower essentially slipping the clutch instead of a clean and quick disengage. I'm driving it now and man it's different. Feels good and solid.
 
#6 · (Edited)
Yes. It sticks out of the drivers side of the bellhousing up top. Should unscrew and just use a punch to pop it and the rubber bushing out. Easy tap and it popped right out. Screw back on and be prepared to bleed the clutch again. 200+ pedal pumps. I had everything apart for the clutch install so it may not be accessible without dropping the trans.
 
#10 ·
yes it is - self bleeding system. Just takes a bit of work...
 
#11 ·
The two days I've been driving so far the shifting issues I had with getting stuck in gear and 1-2 grind is gone. I cant help but thing that is because when I shift now it is a quick clean break instead of a slow release.
 
#12 · (Edited)
This sounds great! I can't wait to do this, it looks like the little rubber restriction just pops out of the valve (from your photo)?
I believe this is the clutch delay valve...looking at it from the engine bay.
 

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#13 ·
That's it. Just take a small punch tool or something similar and push it out.
 
#14 ·
You might have a hard time accessing the small nut on the back to take it off though.
 

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#18 ·
Thanks for all the information! It looks like a pain just getting at it without dropping the trans.
 
#17 ·
Reduces shock to the driveline, slows clutch engagement. On a cold morning with thick fluid a fast 1-2 shift will grind because of this valve.
 
#16 · (Edited)
Jaelliott, thanks for the pics. This mod (along with either a Barton or Hurst shifter) may be a step in curing the common transmission shifting complaints.

In your case, you replaced the clutch assembly as well and went to an aftermarket clutch right? Kinda hard to do an "apples to apples" comparison vs just removing the CDV.

I hope people with shifting concerns/issues find this thread.
 
#20 ·
Jaelliott, thanks for the pics. This mod along with either a Barton or Hurst shifter and possibly different trans fluid, may be a step in curing the common transmission shifting complaints.

In your case, you replaced the clutch assembly as well and went to an aftermarket clutch right? Kinda hard to do an "apples to apples" comparison vs just removing the CDV.

I hope people with shifting concerns/issues find this thread.
You are absolutely correct. I feel as though the difference I can tell the difference between the CDV change and the new clutch. For example the new clutch "grabs" much better for a more solid feel and maybe the motor feels a little more easier revved due to lighter weight. But the CDV change I think is the felt release of the clutch. So the nibbles are less and I have yet to get stuck in first from low speed parking lot driving. Hard for me to explain I guess but I believe that I can discern the differences while driving.

Though at the end I would love to hear from someone with an OEM clutch to confirm or deny my thoughts.

:thumbsup:
 
#21 ·
I believe the CDV does affect clutch disengagement, only when you use the clutch very quickly -as the restrictive valve only allows a small amount of fluid past, this would explain why I get grind as if the clutch is delayed disengaging, it's waiting for the rest of the fluid. I want the clutch to disengage as quickly as the clutch pedal is pressed and it's not happening with this valve in place.
 
#24 ·
So with removing this CDV valve is it safe to assume this would give the driver a more mechanical feel for the clutch sort of like driving a spring clutch from an old school muscle car? During my regular driving i really have no issue with the car other than the clutch grabs pretty high up the pedal when compared to my '63 Impala SS. It is when i'm going for a WOT run shifting at redline is where i have issues with the clutch not disengaging fast enough to bang 2nd or 3rd with out either ginding or me having to slow my shift enough to hit the next gear without a grind.
 
#27 ·
That is exactly correct and what I believe removing the CDV helps with. In my opinion leaving the CDV in actually makes driving the car a lot smoother, easier, and forgiving during DD operations. The only negative with the CDV for DD is that it is in fact essentially always slipping the clutch due to slow engagement and disengagement.

At WOT it is very tough to shift due to the slow disengagement that the CDV causes and thus at WOT is precisely when you feel the benefit of removing the CDV. The shifts are clean and fast with a crisp break. You'll even notice that instead of maybe a 200 rpm increase during shifts you may actually see something like a 500 rpm increase as the clutch/flywheel is freed so much quicker that the engine free revs a bit easier and quicker. At least that was my experience.

My redline is 6600 and I usually would aim to shift about 6400 so that I didn't bump the rev limiter/fuel shutoff on accident. During one of my first runs after breaking the cluth in I noticed that the RPM shot up a bit more/faster during my WOT shifts and I attribute that to the slave quickly releasing the clutch back instead of slowly because of the CDV. Instead the slave actually is freely being yanked back in direct response to my engagement of the clutch pedal.

I hope that all made sense as I was trying to put mental pictures to words.

:guiness:
 
#26 ·
It's not in there tight at all. If you had something like a dental pick or something of the like it could pull out just as easily as being pushed out. The bushing in there with the actual piece of plastic that acts as the restrictor is just wedged in and not really attached or stuck in there. A little nudge, bump, pull, or push and it'll be right on out.
 
#28 ·
subscribed!
 
#30 ·
It was probably in the 75k range but not really noticeable until I jumped down another pulley size started pushing 600hp. My car has been supercharged since around 40k miles so it certainly wore prematurely. I believe most people are seeing over 100k on there stock clutches.
 
#31 ·
Ouch...that is troubling news. I bought mine with 36K on it, I am not really sure who the previous owner was or their driving habits but I am almost certain I can feel some slippage already at 40K. I have heard that the stock clutches on the Challenger are pretty beefy so now I wonder if I may have another issue that could be causing the "slip" feeling. What aftermarket clutch did you go with?
 
#32 · (Edited)
#33 ·
This is right up my alley on what could be causing my cold shifting stiffness through 1-2, and that little "slip" you feel when getting off the clutch... almost feels like it engages, then engages again.


I am putting my car up on a lift this weekend to do an oil change, skip-shift eliminator, and change the trans fluid to Redline.


While I'm under there... is it possible to disconnect JUST the clutch line and dig this o-ring out with a dental pick?


Or does the hydraulic slave cylinder need to come completely out of the transmission.


The pictures provided are hard to follow.




Thanks!
 
#34 ·
IIRC this piece sticks out the top of the bellhousing and you my be able to access it without dropping the trans. Not sure though as I stated I had everything dropped and did it while it was apart.
 

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#35 ·
Ok so I get that the large hex-end of the throw-out/slave sticks out of the trans... but is the little o-ring itself in the large hex fitting, and how deep in is it?


The first picture you posted it almost looks like the o-ring was in the part that unscrews from the large hex bolt and goes to the reservoir. Hard to tell if it's on the throw-out side, or the reservoir side.


Thanks!


 
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