Kabootie, you need to make sure the small tie-rod going from the speed control lever is adjusted correctly. when the spring returns the speed lever to the stopped position (where the roller bearing bottoms out in the lever) the hydraulic actuator on the top of the transmission could be out of adjustment and be supplying enough hydraulic pressure to the tranny to make shifting difficult.
With the engine off, have someone cycle the accelerator pedal and make sure the speed control lever is returning back to the full stop position (bottoming out in the speed lever cam). Make sure the linkage is not binding anywhere (including the dampener stroke) and that the speed control assembly is properly lubricated. Also make sure the cam and roller are clean (no buildup of crud on either).
Also, try raising the rear of the RTV on blocks (in 2WD not 4WD) to see if there is any creep in the drive train after the speed lever returns to fully stopped. If there is any creep, the tie-rod linkage needs adjustment.
This is my country thinkin' just looking at the way it all works.
Do at your own risk. /forums/images/graemlins/wink.gif