Man I hate to say it but mine did the same thing. I replaced the clutch with a PTT dual disk and for the life of me couldn't keep it in adjustment. Played with it the biggest part of the day and decided on a long road trip to Indiana. Made it about 50 miles away when things started going down hill fast and limped it home and found I had smoked the disks already and Steve at PTT couldn't believe with that much wear I even made it home. Slide under the car with a long pry bar or a 2 x 4 and have someone push in the clutch or just push it in and wedge a board from the seat rail to the pedal and go back under and try and move your crank back and forth front to rear. I think max movement in the crank is .008 for thrust wear mine was like .090. /ubbthreads/images/graemlins/banghead.gif I chcked mine with a 2 x 4 against the crank pulley but I had a soild pulley a factory dampner is mounted with rubber and will give false movement.
One question when you accelerate and lift and do it over and over like your trying to get someone to jump did it sound like you had some wear in the gears....clunk clunk....I always thought mine was lash in the transmission, transfer case and rear diff all at the same time ....well it wasn't. It was the thrust banging.
Now for the fix if it is the crankwalk. drop the exhaust, transfer case and pan and if your anal now spray the thrust with brake parts cleaner then use a magnetic base dial indicator and check to make sure but who cares your already in there so just replace the stuff. You can change the bearings without pulling the trans and the flywheel. Just untorque the caps in order and clean clean clean and support the timing belt side with a jackstand or a small hydraulic bottle jack. Just push the bearings around to get the out and do the same to install, use lots of assembly lube to help then reassemble.
Sucks man hate to hear. I wish I would have just went with the previous plan and built an extra motor and just done this instaed of getting pissed and going into Baller status without thinking but little things had been braking once a week and I got sick of it and had the engine, trans, T Case brakes etc all off in about 3 hours tools everywhere and a pissed off attitude for days after.