Is it possible for the thrust bearing to wear enough to effect the clutch release, even though the hot oil pressure is totally normal? I think the pivots are shot on the pressure plate anyway, it barely releases when cold, but the longer I drive the worse it gets. I eventually have to start it in gear.

 

Hot oil pressure? In the clutch hydros?

I've experienced the throw out bearing not sliding on the input shaft due to clutch dust and dirt. I've also had the clutch master fail and not "push" hard enough.

What clutch are you running?

 

Not the hydraulics, on my third one, all have been exactly the same. I even move the slave to the other side of the mount to get the most throw I could.
Oil pressure is the same as it always has been.
The clutch is a LUK Gold and even after some full boost speed shifting and a few drag strip passes it still holds.
What it kinda feels like is the picots are worn out on the pressure plate.
I used my GoPro and the fork movement looks totally normal.
The clutch easily has a couple hundred thousand miles on it, and I have a new LUK rated at 650hp with new flywheel and everything waiting to go in, but I have been too busy/lazy to do it.
Feeling my 64 years these days, but I will swap it before winter and take photos and provide an update.
It is driving me crazy, time to get it done, just hope it isn't the thrust bearing, will check it with a dial indicator when I have the transfer case and transmission off. Planning on doing the rear main while I am there.

 

Sounds like it's time for a tear down and inspection. Maybe the fingers are worn on the pressure plate. Maybe the pivots are also junk, which is hard to imagine even living in PA I've never worn out the pressure plate pivots.

Throw some pics up when you tear it down.

 

It's not uncommon for the pilot bushing, input bearing, or TO bearing to be gone/shot at those miles. Time for a tear down.

My favourite clutch for these is the stock 13".

 

It did cross my mind that the pilot bushing could be seizing on the input shaft. The throwout bearing is smooth and quiet.

Stocker Sachs won't clamp down my engine under boost.

 

Those bronze pilot bushings get obliterated (shattered/gone) in my experience. I was thinking more along the lines of the clutch disc jamming on the input shaft because it's not spinning true.

How much power are you running?

 

I have seen a lot of bronze pilot bearings fall right out of the flywheel when I pull the transmission on high mileage 1st gens.

You also might be on to something with the clutch disc binding on the input shaft.

 

Something that happened to me once was that the pivot ball in the bell housing eventually pierced through the dimple in the center of the clutch fork and left me with no way to disengage the cluthch. (It was kind of like going bankrupt: Gradually, then all at once.) Might pull the dust boot down and shine a Mopar-approved flashlight up in there to make sure you don't have a turtle head poking out.

-Niemand