c6 clutch

[krh]

i have a 2005 conv today going from 1st then 2nd little faster than normal for me, showing off. the clutch went to the floorboard and would not return, lucky i was close to buddy of mines shop, cannot find cause , we had just put a performance program in it, could that be it, my friend thinks it is master cylinder. help please. krh

 

[Tuna]

My 08 did that a couple of years ago. The dealership had to replace the master and slave cylinder, all the fluid and the clutch as it put fluid on the clutch plate. The performance program has nothing to do with it.

 

[Hib Halverson]

"Tuna" is correct. Your clutch problem is unrelated to any reflash of the ECM you did.

The problem is either the clutch itself, or more likely, as "Tuna" suggested, a problem with the clutch hydraulics. I had the same problem with my 04 and it was a faulty clutch master cylinder so I'd check that first.

If the concentric clutch slave is leaking, don't wait to long to fix it or you'll be buying a clutch, too.

Sadly, the labor on a C5/C6 slave is expensive because the torque tube and transaxle have to be removed to service clutch hardware.

 

[krh]

thanks guys, my buddy runs shop never worked on newer vetts but he said same thing not related to program, but it happen when testing after prigram installed, he said master cyl fluid was horribl back gooey, started blleding clutch got clutch back for a second then gone, master cyl coming hope thats it, any more suggestions. thanks krh

 

[Tuna]

The gooey, black fluid appeared to have gummed up the slave cylinder on my car also and it was leaking, which is why the dealer replaced it too. Since mine was under warranty, the dealer replaced everything. Been good since.

 

[krh]

thanks tuna, vette fixed yesterday master cyl doing good now, bet i dont overlook changing clutch fluid anymore, all gooed up. thanks for help. krh

 

[krh]

thanks hib, you dead on master cyl was problem good now, will change fliud more often. again thanks krh

 

[Tuna]

Glad to hear it.

 

[Hib Halverson]

thanks hib, you dead on master cyl was problem good now, will change fliud more often. again thanks krh

Did you just change the master and add new fluid or did you "change" the fluid by bleeding the clutch slave per the Service Manual?

 

[krh]

hi hib, bleed old out new master came with fluid in it . when working on it he kept bleeding and adding new then got new master in and it came with new in it. clutch back way it was, going to change out fluid more often now. thanks again krh

 

[Hib Halverson]

The above is difficult to understand and didn't really answer my question.

So, here's the 411 on bleeding.

To properly flush and bleed the clutch hydraulics, you need to remove the exhaust, remove the torque tube tunnel close-out panel, then bleed the clutch slave per the Service Manual.

If you don't do it that way, you've not bled the system and the contaminants in the fluid (that black goo) will eventually cause the new master to fail.

Good luck.

 

[krh]

hi hib. sorry for the confusion on my explanation we did exactly as you discribed, put it on lift exhaust off other things you stated bleed all old out. fluid clear master in works great. thanks again krh

 

[c4c5specialist]

Hi there,

GM service recommendation is 2 years / 24000 miles for all c5 and c6 clutch fluid.

88958860 or DOT 4 brake fluid should be used.

The issue is HEAT and the fluid boiling when under stress. Thats why header equipped cars have MORE issues as the headers are RIGHT next to the hydraulic lines and need heat insulation.

You most likely repaired your condition by bleeding the system.

All GM masters and slaves already come with the fluid in them, as you have stated.

Allthebest, c4c5

 

[Dad]

Where does the 2 year/24,000 mile service recommendation come from, it's not in my owners manual nor is it in the service manual GMP/05-Y-1 or 2?

 

[krh]

hi dad, i hope you are not asking me cause i dont know about frequincy of changing fluid in clutch, never seen it stated how often , but since i had problems it will be changed more often than every 2 years i am sure. thanks krh

 

[c4c5specialist]

Hi there,

GM released TSB 07.07.31.001 and the following is the cut and paste from that bulletin.

This bulletin is being issued to provide dealers with additional information on servicing the clutch hydraulic system. Please also advise customers of this new maintenance information.
Some cases have been found where the vehicle's clutch hydraulic system was contaminated with water. Higher than expected levels of water in the clutch fluid greater than 2% may cause the clutch fluid to boil. The presence of water in the fluid lowers the boiling point significantly; when this occurs, the driver may lose customary clutch pedal feel and performance.
To eliminate the opportunity for moisture to enter the clutch hydraulic system:

•

The clutch fluid level inspection should be a VISUAL inspection only. Look through the transparent reservoir and observe the fluid level. Avoid removing the cap. DO NOT remove the cap just to top-off clutch fluid. Leave the system closed and sealed. During PDI inspection or routine service, the cap should not be opened for just an inspection.

•	Open containers of DOT 4 clutch fluid have a two week shelf life. DO NOT use fluid if the container opening date is unknown or older than two weeks. DO NOT mix or re-use old fluid. Current service information already covers the issue of reuse.

•	To provide the best clutch operation, it is recommended that the owner change the clutch fluid every two years. Please flush and replace with P/N 88958860 (P/N 88901244 in Canada) or equivalent DOT 4. Allthebest, c4c5

 

[Dad]

That's more like what I was looking for. This issue goes back to when GM said the bad/dark looking fluid was just from the carbon black that was used in the manufacture of the seals in the clutch system. Now GM states that this information should be passed on to the users/owners of these systems but do not or did not do so, just the dealers. They state 2 years but you (C4C5) state that your preference also includes 24,000 mile, which I think is a benefit to us all to abide by.

My issue with this started when my dealer charged me for 5/8 of an ounce fluid for my clutch. They thought I was upset because of the .82¢ when all I wanted them to do was tell me why they were looking into my clutch reservoir. They said it was because the fluid looks so dark and wanted to know what I had done to it. When I ask them how they checked it they said they just, "take the cap off and look, how else would you do it?" It all came to a head when they couldn't tell me how long the bottle of DOT 4 had been is use. After they bled the system and took the .82¢ off my bill they then replied to my question if they had greased it that, "there are no zerks on these cars".

I've never been back even though they sold out after over 50 years as a dealer. :eyerole

 

[hunt4cleanair]

Why the emphasis on "VISUAL inspection only." Eliminate moisture and contaminants from entering the system?

The clutch fluid level inspection should be a VISUAL inspection only. Look through the transparent reservoir and observe the fluid level. Avoid removing the cap. DO NOT remove the cap just to top-off clutch fluid. Leave the system closed and sealed. During PDI inspection or routine service, the cap should not be opened for just an inspection.

 

[NORTY]

Why the emphasis on "VISUAL inspection only." Eliminate moisture and contaminants from entering the system?

Yes, the fluid is hygroscopic. It will pull water from the air (via humidity.)

Also OP~ You might want to use Ranger's method of changing the majority of your fluid on a monthly basis. It's easy as you don't have to turn any wrenches or get under the car.

If you want to get under the car and do it per GM guidelines, it would be better but it's a labor intensive procedure.

Someone makes a drain type device for the slave (actuator, in GM speak) that greatly reduces the labor involved to replace the fluid.

 

[hunt4cleanair]

Also OP~ You might want to use Ranger's method of changing the majority of your fluid on a monthly basis. It's easy as you don't have to turn any wrenches or get under the car.

Where do I find "Ranger's" method?

Nevermind...Got it!