Clutch/Transmission Diagnostic Help Needed

[Chim-Chim]

Hi all,
I'm having some problems with my transmission. It happened at the track on Monday. 2nd session in I started finding the shifting to get harder and by the 4th session, I basically had to really force every gear. Managed to limp home in 5th without shifting (track is right off the freeway).

Symptoms:

Clutch seemed/seems fine. No hint of slipping and it was grabbing without issue right up until the loss of shifting

When the car is off, I can shift into every gear without a problem--feels perfectly normal.

When the car is on, with the clutch pedal fully depressed, I can't get into any gear. It is as if the clutch pedal isn't depressed. I've tried rapid pumping, slow pumping, etc... and still nothing.

When the car is off, the clutch pedal effort seems normal. When the car is on, however, the clutch pedal effort seems harder.

What I've done:

I pulled the tranny and replaced the hydraulic throwout. I also inspected the clutch as best I could without taking it apart and nothing looked abnormal.

I pedal bled the system (many long, slow pumps while the front left was in the air). I also ran out and got a vacuum bleeder when the pedal bleeding didn't work. I have gone through several vacuum bleed cycles per the factory service manual with no change to the clutch feel.

The system does hold a vacuum (I currently have it under 20 in. hoping it is still a bleeding issue).


Any thoughts on next steps? If it is a hydraulic system issue, then it could be the clutch master cylinder? I'm assuming it could probably mimic the same symptoms?

Could it be something with the clutch assembly? Do pressure plates ever fail with these types of symptoms? Maybe the hydraulic system is working fine, but the pressure plate isn't releasing?

 

[JeremyH]

What clutch, how many miles on it?

Trans sounds fine, leaning towards clutch, slave or master issue.

Also what year is your car? In 05 early 06 they had a bleed valve on the line that would fail and leak fluid and the clutch would not fully release.

 

[BruceH]

You are describing exactly what my car did when the slave went out. Since you have replaced the slave more than likely it's the master. Have you looked at the master, carpet, and nearby structure?

 

[Chim-Chim]

What clutch, how many miles on it?

Trans sounds fine, leaning towards clutch, slave or master issue.

Also what year is your car? In 05 early 06 they had a bleed valve on the line that would fail and leak fluid and the clutch would not fully release.

It's an '06 with no bleed valve on the line.

You are describing exactly what my car did when the slave went out. Since you have replaced the slave more than likely it's the master. Have you looked at the master, carpet, and nearby structure?

No evidence of leaking inside the car. There was some fluid in the general area in the engine bay, but it looked like it was the usual track day leaking out of the reservoir cap. But...now that I think about it, there was a lot more than usual puddled below.

Oh well, new clutch master is on the way. At least it is easier than dropping the tranny again. I'll update if the new master fixes it.

 

[lil_sixer]

Definitely not a transmission issue,definitely clutch..
Honestly I would just get a new clutch kit,thats what it sounds like..

 

[702GT]

Clutch pedal should not get harder when the motor is on. The clutch hydralics is an isolated system. Definately sounds like master/slave went out. I'm leaning towards master only because while you can still bleed and pump a master it might not hold enough pressure in a closed system to push the slave out. Replace both IMO just so both are new.

 

[Chim-Chim]

Now I'm getting frustrated. Replaced the clutch master today. Absolutely no change. I've vacuum bled and pedaled it through too many cycles to count, and still nothing.

So I've basically replaced the entire hydraulic clutch system, yet the problem isn't fixed.

Clutch? Tranny?

 

[techcargt]

Clutch disc has more than likely come apart .

 

[CRICKET]

Mine did the exact same thing last Monday. After calling a flat bed to come get it, transmission was lowered today and the clutch and pressure plate is toast! I had a couple of pieces of metal that broke from the pressure plate bouncing around inside the bell housing! Symptoms you described were exact. Putting in new clutch tomorrow.... and replacing the slave just to be safe...... Good luck, I'll update you when I'm finished.

 

[CRICKET]

pic speaks for itself!

 

[Chim-Chim]

Thanks for the pic! When I had the tranny out to do the throwout, nothing looked broken, but I didn't pull the pressure plate. I'll be replacing the clutch in the next few days, too, I guess...

 

[702GT]

View attachment 29667pic speaks for itself!

Original and Extra-crispy all rolled into one clutch!

 

[CRICKET]

^ lol ^

 

[JeremyH]

Yeap def next step is to pull the clutch.

 

[Chim-Chim]

Clutch is out and it looks fine. Nothing out of sorts, flywheel and pressure plate surfaces look smooth and clean. The disc has plenty of material left--enough that I wouldn't hesitate putting it back in.

I'm at a loss at this point. I have a new clutch kit that will be here tomorrow, but I'm not convinced the pressure plate is bad.

Seems like something in the tranny is shot. I don't know enough about the inner workings to venture a guess, though...

 

[skyline247]

I'm no expert, but is it possible that your problem may be with the gear synchros or the shifter? I could be completely wrong, but I figured I would throw in a guess. Sorry I can't help you further. Hope you figure this out soon.

Sent from my PC36100 using Tapatalk

 

[JeremyH]

Doubt its a trans issue if it shifts right into gear no problem with he car off. Any signs of heat or warping on the pp?

 

[Chim-Chim]

I'm no expert, but is it possible that your problem may be with the gear synchros or the shifter? I could be completely wrong, but I figured I would throw in a guess. Sorry I can't help you further. Hope you figure this out soon.

I'm no expert, either! I truly appreciate any and all suggestions at this point. It's definitely not the shifter, as it works fine with the car off and shifts into all gears without a problem. I don't know enough about how the 3650 works to know if it is a synchro problem, but I was always under the understanding that (1) synchros usually start to degrade in performance before completely failing; and (2) the symptoms typically affect certain gears, not all.

Doubt its a trans issue if it shifts right into gear no problem with he car off. Any signs of heat or warping on the pp?

No signs of heat or warping. Both the pp and the flywheel look very good. I've never launched the car or been tough on the clutch, but road course work can definitely heat things up, so who knows if that damaged the pp in some way.

New clutch arrived today, so it and a new pilot bearing are going in tomorrow most likely. Crossing fingers...

 

[aleborjas]

the presure plate is DONE it does not release the disc completly and hot is worst, raplace it with a EXEDY mach 400 clutch that is the best single disc on the market i've tried all brands... and lost too much money!

what brand did you got?

 

[Chim-Chim]

the presure plate is DONE it does not release the disc completly and hot is worst, raplace it with a EXEDY mach 400 clutch that is the best single disc on the market i've tried all brands... and lost too much money!

what brand did you got?

At this point I am really hoping it is the pressure plate. I went with a RAM kit after talking with a few locals who have had good success with it. I'm at bolt-on NA power levels and never launch it, so a stock setup should be fine.

And if this one doesn't last too long, I've become a pro at dropping the tranny!