I went to the dealer today because they called after three weeks that my car was finaly fixed. The tech and I took it for a ride and while just driving around town we had no issues. We took it to the Airport for a hard pull and the same thing! Even though it has a brand new transmission and slave cylinder-When shifting from 4th to 5th at 120mph and 7500rpm the clutch stayed half way down...........I had to put my foot under it to pull it back up.........................
This is so aggrivating!
The car has now been in the shop longer then I owned it!
Any suggestions?
the tech said maybe a bad master cylinder.........

 

The 'Stang doesn't like you because your dream car's a Chevy.

 

Man, if I was a dealership throwing parts at it, I would have done a clutch/pressure plate before throwing a tranny at it. How the hell could a tranny be at fault?

 

this may be true..... but they shoulda replaced the clutch from the get go

 

Some clutches develop a vacumn under high RPM. This vacumn can hold the clutch down to the floor. That being said, why would it not do it in any 7500RPM gear selection? The only thing I can think of is 4rth gear 7500 allows the clutch to stay in that RPM longer allowing it to build more vacumn. The 1/2 and 2/3 shift happen much quicker and could allow the clutch to not build as much Vacumn.

I would really be looking at the clutch. Just a thought from a Ford Tech.

Joe

 

If you have time go back and read my post "Clutch on the floor"
When the clutch or slave cylinder failed I hit 5th really hard and it destroyed all of the syncros.....After that it would not go in 2nd or 5th.....I told Ford I did not want a rebuilt transmission.
So thats why it has a new trans..........A buddy of mine who owns a race shop thinks its the master cylinder. He said if they start giving me issues I need to start mentioning Lemon Law! I don't want to resort to that but I also don't want a 40k Boss that does not perform!

 

I have had that screen name long before I even thought about owning a Ford. There is no Pun intended with it.
I only keep it because it's easy to remember on all of the forums i visit. Right now though I would take my Vette back..........I never had one issue with it! even after 550rwhp through a stock trans.
I'm not bashing the Boss I'm sure many have great luck with thier car,but I can not praise it either just due to the personal experiance I have had so far.......

 

Are you thinking the clutch or pressure plate?
I will pm you my cell# Please call me
I would like to have you speak with my tech

 

After getting more details from you over the phone I have a feeling the clutch is building heat. Heat is tranferring from there into the slave cylinder and causing the fluid to boil. That will then cause it to get air bubbles in the fluid and thus causing hydraulic issues with the clutch.

These are some things to discuss with your service tech.

Joe

 

Very interesting, what would you think would cause the clutch to build that much excessive heat...Are you talking about slipage or just the nature of being under a heavy load at high RPM? Just trying to fully understand.

 

I have fortunately not had this issue and I track my car a lot. I've had DOT4 fluid in since day 1 and I'm assuming that's helped. I did a VERY complete flush from Super Blue to Amber Type 200 this spring through the brake sytem. I've noticed when I bleed the brakes after each track event that I'll find some blue in the master cylinder reservoir. It HAS to be coming from the clutch line as I flushed until there was no trace of blue in the brakes. Subsequently I've been sucking some of the fluid out of the reservoir before each brake bleed to make sure I'm continuing to flush fresh DOT 4 into the clutch line as I'm using it.

 

OP is telling me he can smell burnt clutch after a hard run. A pressure plate that has not completely gone "away" will only slip in higher gears(greater load vs mechanical advantage)

I suspect he may be building heat inside the bell housing(under high rpm) and it is transferring into the slave cylinder. He may need a clutch replacement along with the fluid being flushed and new placed back into the system.

I am not saying I am correct. It is just a feeling I have given the details I have been told.

Joe

 

All seems to be good now!
they flushed the fluid and changed it.....Im thinking it was air in the line but I'm not sure. I do plan to put the 302S steal line vs our dinky plastic one.

 

Glad you got it sorted out. Wonder how air mangaed to get into a sealed system? Heat/bloiled fluid? Interesting.

Joe

 

Thats a very good question....Maybe when he swaped the transmission