Transmission will shift to park, but will not engage any other gear.

Was driving about 40mph when I felt like the truck went into neutral while in (D)rive. I coasted to a stop. Gave it gas, only reving engine with no go. Switched gear to park and it held. Tried to shift into other gears (R), (D), 1,2,3 and nothing. Was as if all gears where neutral. Thought it might be the Neutral safety switch, replaced n stil nothing. Checked fuses, linkage, fluid, all good.