push in the valve spools manually. if no movement you have hydraulic problem. there might be a pressure test tee in line on left side that runs at angle down side of transmission. mine runs 20-50 psi which may be low. mechanic told me 200 might be good.
pressure regulator is plug on left side of shift valve. has cap, shim, spring, pointed plunger. add shims to increase pressure.
we changed our solenoid valve because of bad coil and desire to eliminate that as a cause of the problem. if it doesn't get full 12 volts it doesn't work. amp light coming on dim when shifting indicates a draw somewhere. ours requires a solid snap of the switch to shift. new switch is like $600. I made a small floor plate with the accelerator to be able to get at valve while running. sometimes put the full floor plates on and it will quit working. that one I can't figure out.
p