Re: on my way to the track
here's what you do to check shit out....
jack the truck up, probably best to put all 4 wheels in the air since youre gonna be shifting the trans and stuff.
once the truck is in the air, go under and pull the shifter cable off the pin. Given that both the trans and gear selector are still in park, you should be able to put the cable loop back on the pin WITHOUT having to move the shifter linkage at all, or at least less than a hair.
If you cannot do this, then that could be part of your problem.
If you can get it on, then move the shifter into R, then move the arm on the transmission 1 click into the reverse position. Check to see if you can get the cable on the pin again.
Check and see if you can do that for all positions, R - 1. If everything is off just a little bit, try adjusting (bending) the bracket on the trans till things line back up.