Powerglide troubles
 

I ran my truck for the first time this year a couple weeks back. Had a few teething issues I resolved except 1. I have no high gear. It is a BTE glide with a pro brake and a BTE convertor. Convertor seems to be fine, No trouble with it taking reverse or low, just no high gear. It will load the engine slightly when you put it in drive while idling, but absolutely no movement. No discernable odd noises or clunking, etc. I doublechecked the shifter cable, seems to be correct. It worked fine the last time I ran it, and it's a pretty fresh tranny, I'd say 20 passes or so. Any ideas on what to look for during the teardown?

Well if it worked the last time out I'd rule out the cable being out of adjustment.
To me it sounds like a sticky valve in the valve body.
I'd pull the pan and filter and see if everything looks normal I.E, broken bands tabs, servo pin broke etc, then pull the valve body and check all the valves for proper movement.
Goodluck, Charles

That's pretty much the plan, I'm just kicking around for suggestions so I'll sound informed when my tranny guy and I tear it down. I'm still pretty new at these slushboxes...

Well, in between rain squalls from Gustav, we tore down the tranny. The valve body mounting bolts worked loose and it blew the gaskets. Loss of fluid pressure wiped out the Kevlar band and the high gear clutches and steels. Looks like all that's needed is the above mentioned parts and some Star-loc washers...