"sparky",
I did figure out the problem, with the help from several other bolters specifically Dave in WA. Unfortunately most folks ask answers to problems, but few post results. With this issue, I am similarly guilty.
I narrowed down the symptoms to be the result of several issues, and in putting the assembly back together, I unfortunately didn't definitively isolate the absolute failed part as testing each was just too much work.
1) I checked all of the clutch disks I have and found that as Dave stated, some have excessive runout causing the clutch to drag. The disk I had in the truck at the time of failure had quite a bit of runout.
2)I installed 140 weight gear oil so there was slightly more friction allowing the transmission shaft to stop spinning a bit faster.
3) I checked the wear on the lugs of my "freshly rebuilt" pressure plate, and found them to be VERY worn and out of specification. This I think was the true point of failure as the wear point between the pressure plate cover and plate lugs allowed the two parts to bind "sometimes" and cause shifting problems. See images below.
[img]http://www.surfacezero.com/g503/data/3176/medium/IMG_7299.JPG[/img]The pressure plate on the left is a new NORS, the "rebuilt" one on the right
I don't recall the manual specifications for this wear, but the defective plate was way out of specification at 0.040.
As for losing sufficient adjustment threads on the fork, I believe that is an artifact of years of use and indiscriminant machine shop surfacing's. Each time the flywheel or pressure plate is surfaced, the assembly gets shorter which will show up on that little "shepherds crook" looking adjuster. even a slight 0.020 here and a 0.010 there is magnified at the adjuster.
[img]http://www.surfacezero.com/g503/data/3176/medium/IMG_73001.JPG[/img]Note the difference in the surface depth on the NORS pressure plate surface on the right and the "surfaced" one on the right.
Anyway, after checking disk runout, adding thicker oil, and getting another pressure plate (with no wear on the lugs) solved my shifting problem. Now the only problems the truck shifting are purely "operator error".
Hope this helps.
Paul
