4l80e acting weird
 

Have a 4l80e that I pulled from my old truck to put in my 03. Rebuilt it last year and has roughly 5k miles on it. Ran great when pulled. I had it covered for the winter and recently got it installed in my 03.
Filled it with fluids, checked torque converter spacing, and wiring. Fired it up, moved forwards and back yesterday. Topped off fluids. Went today to test it out and only went forwards in all gears, including park. Shut it down, rechecked everything. Started backup and doesnt move at all.
line pressure was 200psi in reverse, and 100psi in forward gears. No movement with throttle. Pulled main plug and had 200psi for pressure. Reconnected harness , and checked hptuners. Had TC input shaft speed, no output. Rechecked torque converter spacing.
what am I missing ? I don't imagine anything internally went bad over winter, it was covered but anything is possible. Any tests I can do before I pull the tranny ?

I would drop the pan and check that the manual valve is still connected to the shift cable cam.

Thanks I am going to drop the pan today and see whats happening. I figured worst case is the forward clutches welded themselves together, which I have read can happen from low fluid. I didn't attempt to move it until fluid level was correct, so I can't imagine that is an issue.

Dropped the pan and found my shift selector rod is broken again. The piece that goes into the case and held in my a roll pin sheared off. Do they make a stronger one ?

I checked the manual valve and its straight. Goes on valve body easy and no hang ups.