Clutch Problem

Its driving the gearbox regardless of the clutch pedal movement.

When the pedal is depressed the pressure plate face moves away from the flywheel and the clutch disc should also follow very slightly...my guess is it can't.

Adrian

One thing I did find - I keep a pretty good maintenance log (a habit from working on airplanes, plus my memory is crap). I went back and looked where I replaced the clutch linkage (actually 2 years ago). I do not see anywhere that I replaced the cable like I thought. I just replaced the torque tube (studs, seals, springs, etc.), and the link rod. I then wrote: 

"...adjusted pedal free travel to spec. (1-1/2 in.)"

Hmmm...I'm not sure why I went with 1-1/2 in. instead of the 1 in. listed in the manual, but I know there is a Service Letter somewhere that specifies changing the free play from 1 in. to 1-1/2 in. because of a change in the length of either the cable, the link rod, or maybe both. I'm not sure why I thought at the time this would apply to me, but that must be where I got it from (I know my new link rod is a bit longer than the original I removed). I also wrote that the clutch tested "Good" afterwards, but honestly I don't remember thinking that I had the problem resolved, so I wonder if my log entry may have been a bit hasty after a quick check that seemed to go well. I wasn't driving the jeep at the time, other than around my back yard to check for function while I was working on it pretty regularly.

So, will try to check all these things today. Thanks for all the helpful input, it is much appreciated.

I began by checking the free travel on the pedal - 1-1/2 in., just as my logbook noted. Next, I removed the cover on the top of the bell housing so I could get a look inside at the clutch. There was no evidence of rusting on the input shaft, most likely thanks in part to a bit of a rear main seal leak.  Still, I sprayed a few shots of PB Blaster on the splines and pumped the pedal several times while watching the disc to make sure it was traveling back and forth on the splines when it was released by the pressure plate. This appeared normal. Next, I started the engine with the trans. in Neutral and watched the clutch. When I pressed the pedal in, the disc continued to spin for a while, but slowly spun down to a stop and I could put the trans. in gear and out with no problem. Back to neutral, release the pedal and let everything spin for a bit, then push the pedal in, and the disc continues to spin...and spin, and spin, with no end it sight. No way to get the trans. in gear like this. So, I shut it down, put it in gear and re-started with the pedal pressed down. The Jeep lurched an inch forward with the first bump of the starter, then the engine started normally and the disc was stationary, and I could shift to any gear. But, as soon as I released the pedal and let the disc spin, it would not stop spinning when the pedal was pressed again and I would have to stop the engine to start the process over again.

OK, so I crawled under and re-adjusted the pedal free travel to just shy of 1 inch (like 7/8 in., or so). I re-started the engine and tested - no improvement in the clutch release. I can't really adjust any more free play out without having the release bearing permanently engaged, so I've got all the slack out of the linkage that I can get away with. Finally, I sat in the seat and depressed the pedal with the trans. in Neutral, and took a long screwdriver and poked around the clutch disc with it. At first, it was stuck, but with a little prying, I could get it to free up and then I could spin it fairly easily using the screwdriver as a pry bar.

Bottom line, the issue is not linkage, or travel, or free-play adjustment, etc. The issue is that the clutch disc is somehow binding on either the flywheel or the pressure plate when the engine is running with the pedal released. Once this occurs, nothing seems to be able to jar it loose other than shutting it down and re-starting it with the trans. in gear and the clutch depressed (whereupon the first bump of the starter will cause the Jeep to lurch forward an inch until the disc breaks free and all is well again until the pedal is released again).

At this point, I do not see any solution that can be obtained without a split of the trans/engine and removal of the clutch and pressure plate (which of course means a replacement of same). I cannot figure out where the binding is occurring, since I can see the disc move rearward when the pedal is depressed. Perhaps, as was suggested, the lining is delaminating and fouling the interface between the disc and flywheel (or disc and pressure plate). Anyway, I don't see a way to figure it out without a teardown.