1990 pick-up 4x4 won't shift

I have changed master and slave cylinders but vehicle still won't shift.
With engine off shifter moves smoothly. With engine running it's about impossible to shift most of the time. Some times it shifts like new so the clutch itself can be ruled out as culprit. I don't think fork is bent either because sometimes it works fine. I have bled it several times can't imagine any air still stuck in system. I am all out of ideas, what should i do?

Shift lever pilot bushing # 33548-31010 (green)=$7 CDN
Shift lever seat # 33505-35020 or 33505-35030 (white)=$16 CDN

Note: the 2 above #’s fit all trannies:G,R,W series (22R,R-E,3VZE)84-95.5,no need for entire shift lever retainer (85-95.5 pre-Tacoma)

http://www.4runners.org/articles/shift/
http://www.off-road.com/toyota/tech/shifter/index.html
http://www.marlincrawler.com/docs/shifter_seat/index.html

Sidney® ™
Repairs tv's,vcr's,home/car audio out of my home
E-mail:[email protected]
Dartmouth,Nova Scotia
Canada
1985 Toyota 4-Runner,solid front straight axle,factory cruise control,sunroof,22R-E,W56,RN60LV-MSEK,rusted rear step/towing chrome bumper with 246 000 KM