The NSBU switch is attached to the left side of the trans-- if it gets water inside, it can cause all kinds of problems. Common problem- with 5 speed trans. (May show Shift Range Inhibited)
I suggest you replace the switch and check the fuses- Buy from Allison or auto parts (dealer $$)- the short could have blown a fuse.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.