1998 GMC 2500 automatic 4x4 transmission problem

Put truck in reverse it backed up about 30 feet then
put it in 1st gear it started to pull but then just like
it went into neutral just revs up so I put it back in
reverse but it just revved up won't go into gear so I
pushed it to the side of the road came back to it a
week later and tried to put it in drive it still revved
up like it was in neutral put it in reverse and it did
the same thing so I put it into park then shifted it
back to reverse and just barely patted the gas
pedal and it started slowly backing up so I stopped
and shifted to drive and it was like it was in neutral
again so back to reverse and it backed up about 30
feet then was like I hit neutral again  just revs up is
it a compression problem or what could it be the
torgue converter? I put in 4 hi it backed up about
10 to 15 feet then same thing happens just like it
hits neutral does my transmission get hot and stop
working or what could it be?