Clutch Master or Slave?

Ron

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1996 GTS - Clutch engages very low sometimes after the car sits for a while. Stays that way for 5 or so shifts then returns to normal. Pumping the clutch doesn't seem to help, instead actual engagements are required for it to return to normal. Daily use maintains normalcy for the most part, though an occasional low engagement still occurs. Holding the clutch depressed for a period of time does not leak to engagement, like a brake master might slowly leak to the floor. No observed fluid leakage, master is full, 26K miles, fluid changes / bleeds every two years.

Suspect seal hardening but given the lack of leakage would this point more to master rather than slave? I probably should know this, but it's late....

Thinking of trying Tom's (F&L GoR) Aviation Hydraulic fluid idea ( http://bit.ly/g7Zz6J ) to swell the seals but thought I try to figure out the culprit first.

Thanks
 

-FROG-

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Well, I have done 2 Master / Slave cylinders and form my problems, you KNOW when you r slave cylinder is leaking. Your reservior will be low on fluid and you can also see a drip, or you can run your finger in the bell housing and see oil.

I am wondering if it is your master cylinder. It really doesn't matter in a sense where the problem is because when you replace the master, you should ALWAYS do the slave cylinder too, and vice versa. I would go ahead and replace both. It's not too expensive but pulling the tranny is a pain... It can be done in a weekend though. Just don't ask me to do it... grrrrr.....
 

RobZilla

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Throw out bearing could be wearing/worn out. Pressure plate as said above.

Start with a fluid change and a couple of phone calls then tear into it and start inspecting if you are gonna do the job yourself.

:usa:
 

dave6666

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If your clutch is near worn out and not really engaging well because of said wear then the 5 shifts --->> working better could be due to heat buildup and subsequent expansion of the parts closing the tolerances back up.

At your mileage you are due for a clutch and slave. Just do it.
 

2easy

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I dont think you have a seal problem. I agree with RobZilla that you should start by replacing the fluids. It may be an easy fix and replacment of these fluid can do no harm. Dave666 has my vote with the problem most likely being excessive wear on the clutch/pressure plate. The number of miles on the car plus the fact that the problem only goes away once the clutch and plate have expanded due to friction heat are good clues and support his guesstimate. Might want to take it down the road in 1st or 2nd gear (avoid wheel spin) and give it alot of throttle, then let off just as aggressively to confirm this. You should feel the clutch slip especially when downshifting, the gear shifter and clutch will be fully engaged but the car will take a few seconds to respond to your inputs. This may not give you 100% confirmation based status of your clutch, but is a decent litmus test in most cases. You sound familiar with mechanics, so Im sure you know what Im talking about. Remember not to go too far from home in the event you reach catastrophic failure. Good luck!
 
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Ron

Ron

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Thanks guys - Clutch / flywheel / pressure plate was replaced at about 12,000 miles due to an oil leak out of the cam plug, so the current clutch has less than 15,000 miles on it, though the throwout bearing and slave cylinder is original 1996 vintage. Not abused so while anything is possible I'd find it shocking if the clutch wouldn't last more than 15K on a stock engine. Zero slippage under full throttle in high gear or while downshifting. No smells of slippage either. Very familar with those things from my Trans Am days. And yes, need to resolve as it's no fun to drive if you can't trust that it'll bring you home. Drove my Trans Am without the ability to disengage the clutch (start in gear, matched rpm shifting, stall to stop) but not sure the Viper is able to do the same or better said, I'm able to do it in the Viper. Have lift and trans jack so not an impossible repair task, just prefer to diagnose before I dig in.

Have a spare clutch master cylinder so I'll eliminate that from the equation first. After that and fluid change will report back. Thanks Dave for the lead on the write up.
 
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2easy

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Hey Ron, here is some more to chew on. I tried to look up your symtoms in my service manual and came up with nothing so when in doubt, I use the search button. Would you say it feels "Chunky or Sticky" when shifting? This seems to occur only when the vehicle is cold, and disappears when warm as you have stated. Im uncertain if you have searched this problem within this site, but when you do under the heading "clutch" numerous threads turn up. After reading a few, I am wondering if your problem is generic with the type of transmission fluid you are using. Stock is Mopars Synthetic Manual Transmission Lubricant 75w-85 (Castol I believe) If you are not replacing this product with something else, like Synthetic Dex VI you will continue to experience the symptoms you speak of when shifting. May not be your clutch after all.
 
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Ron

Ron

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2easy - Nope, trans shifts like a dream. Mine came with Dexron from the factory but I switched to Syntorq (meaning the later Mopar synthetic factory fill) when the car had about 5k miles. Recently switched back to ATF, this time Chrysler ATF+4 and it shifts better than ever.

I can clearly feel the softness of the clutch when it's engaging low then firms up when properly engaging.

Thanks for the idea though...
 
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Ron

Ron

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Thanks Dave for the advice - Also that is one heck of a write up! I PDF'd it and it's hanging on the garage wall just waiting for a warm spring day -
 

RobZilla

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Advance Auto Parts: Ball Bearing by National - Part 614061

Above is likely your culprit. If you order the slave this part is included at a cost of around 260 bucks total / give or take.

Just the bearing is 35-40 bucks at the local parts store.

When you get into it and start tearing it apart you'll see that grease globs which have gotten to a more solid state are littering the part. Also the metal ring on the front will wobble and feel a lot looser than a tight new one which has a very slight loose feeling to it.

Like other have said it's probably time to do a slave as well but hell if it's not leaking and a fluid change gives a stiff pedal feel you may just need a new bearing.

Hope this helps.

:usa:
 

dave6666

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Assuming it's been more than since last week when I've had the tranny out, I would never again not replace the clutch/PP/slave assy when the tranny is out. $500 for those parts is way less than my time repeating it the next week because I didn't do it this week when it was right there in front of me. And yes, I donate the gently used and not used up leftovers to the needy ;)
 

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