Truck won't go forward, goes backwards in neutral

[mellonhead]

The other day, I got off the highway and stopped at a red light, and when I went to go after the light turned green, all the sudden my truck would no longer go. I put the truck in neutral and let off the clutch and it started going in reverse! I tried to put it back in gear and it wouldn't go into gear. I turned the truck off and it went into gear, but when I restarted and let off the clutch, it immediately stalled. I didn't hear any strange noises or smell anything unusual prior to this happening. Seems like it came out of nowhere. Can a transmission go just like that (that is what the "car people" I know seem to think the problem is when I describe the issue)? Any help, tests, or advice would be appreciated. I'm pretty much a novice mechanic, so I apologize in advance for anything stupid I might say. Thanks! (probably should have noted that the truck is a 1995 Nissan hardbody with a 4 cyl, 5-speed and around 115k miles)

[PapaSmurf2k3]

Yeah, that is weird for sure.
I guess if the shifter mechanism or turret gets messed up, that can happen, but its gotta be pretty rare. I'd sage you might have to pull the shifter mechanism and look at the bushing on the end of the ball and make sure its still there. If not, it might have been pushing the turret in directions it isn't supposed to go. I'm sure you still have the correct gears SOMEWHERE in there, but its no longer in the proper gate pattern.
If all else fails, you might have to pull the trans and crack it open to see if a fork is messed up or something (or just replace the trans all together if you don't feel like messing with it).