Clutch sticks when engine warms

I have a question that I want to ask the group while the engine of my 88 Wrangler is out. It's a 4.2 L6 with the BA 10/5 trans. I've gone through some growing pains trying to get the clutch working properly, so I've tried a lot. Nothing has worked

Here is the problem:
When the car was drivable, the clutch would start to stick progressively worse as the engine warmed up. While I cannot correlate it for certain to engine temperature I can assure you that it went into gear just fine when the engine was cold and started struggling when it warmed... I let the car warm in my garage from a cold start and ensured that warming the engine while not driving it did indeed cause the engine to stick. I drove the car over and over again and each time it behaved the same way.

What I suspect the problem to be:
I'm suspecting that it's sticking because the flywheel / clutch / pressure plate was getting a good amount of oil leaking onto it because I screwed up and didn't tighten down the bearing cap of the rear main seal bearing when I had the engine out the last time! The car has always leaked a little oil but never that bad before so I fully suspect my snafu was the main culprit of the bad oil leak. Now my Hanes manual says that oil leaking onto the clutch could cause it to stick, but my intuition told me that it was more likely that it would slip instead of stick. Moreover, now that the engine is out again and I've taken off the clutch / pressure plate, the clutch disk doesn't look too bad! There is definitely oil all around the area but the clutch doesn't feel at all sticky when I run my finger across it. I would have expected to see some 'gunk and build up' on the clutch disk if it were truly sticking because of an oil leak.

What I have done already:
The clutch disk, pressure plate, slave/throwout are all new. So is the hydraulic line to the master cylinder. They were replaced the last time the engine was out in an attempt to replace the blown slave. (BTW clutch worked great before it blew out... it did leak fluid, but never stuck like it does now) I have inspected the master cylinder for leaks and I have found none. The clutch fluid level has not dropped at all. So I feel confident that it's not a slow leak of fluid from the hydraulics. (Thought I suppose it is possible that the leak is somehow internal to the whole unit)

Lastly, some weird observations that might help diagnose the problem. The clutch fluid is discolored... it has brown debris that is easily visible from the master reservoir. I've not given it much thought as I just suspect its oil from the bellhousing area that has somehow infiltrated the system. Also, one of my pressure plate forks is bent, only slightly, but absolutely noticeable. I figured it was from a misalignment of the tranny to the engine when I reinstalled the engine the last time.

I don't want to take the engine out again! If someone wants to see pictures, then post what you want to see and I will gladly oblige you.

Thanks in advance for any helpful advice!
Jeff  

First, you're dealing with two very problematic pieces. The BA/10 and the internal slave/throwout.

It's surprising you're even dealing with the tranny, at this point in time because they don't usually last long and most replace them with an AX15 when they break. Jeep only used the BA/10 for a year and a half. Halfway through the '88 model year they were causing so many warranty problems for Chrysler, they switched mid-year to the AX15. But the internal slave lasted until '93.

But since you already bought a new internal slave/throwout, you probably don't want to throw it away. For the price of the internal slave you can practically get a '94 or newer AX15 that uses the external slave. Something to think about in the future.

Obviously, contaminants are a bad thing, but you're working on that problem. Alignment of the input shaft and squareness of the tranny to the motor is critical to a properly working clutch. Here are some things to check that affect alignment and squareness.

The alignment dowels should be in good condition. Bolts don't align the bellhousing. The pilot bushing must be the correct size and be in perfect condition, and should always be replaced when replacing the clutch components. Also, the front bearing of the tranny should not have any lateral play and the front bearing retainer should also be in good condition allowing the throwout bearing to slide nicely.

Another thing to check is flywheel runout and crank to bellhousing bore runout. This requires you to remove the bellhousing from the tranny, mount the bellhousing on the motor and then take measurements with a dial indicator mounted inside the bellhousing. You have to make sure that the mounting faces are clean and that there are no burrs to keep the bellhousing from aligning correctly with the motor.