1985 Toyota Pickup No Shift

This is a 22RT engine.
When put in reverse works fine. Put in drive and goes in gear, but when I accelerate it starts out in high gear and just won't go.I can put into lo and manually shift it up and down through all gears and goes just fine. Just will not shift up or down by itself.
I checked all connections to trans. And there is nothing obviously disconnected, torn or leaking.
Fluid level is good.
Any info will be appreciated.
Thanks, Steve