My truck won't move when I put it into gear.
I have a 77 chevy c10 with a turbo 400
tranny it won't go in gear when I put it
into drive and makes a humming sound
but if I put out in L1 it moves just fine
and if I go into drive once I get moving it
shift fine from there the tranny fluid not
low just need an idea what it could be.