1997 Chevy Truck Won't Move when put into gear

I have a friend that has a Chevy truck and one day he was driving it and it was like he put the truck in neutral. It wouldn't move. Now the truck will not move when put into any gear. Once in a while you can put it in gear and drive it a little ways then it quits and sounds like it's in neutral again. Do you know what could be the problem?

If it helps we do have a OBDII scanner, hooked it up to the truck and it gave us these codes:

P0740
P0753
P0785
P1860

Thanks

Jaime