2008 Pontiac GXP

May 2008 Pontiac GXP will go in reverse and
move fine but when I put it in drive it won't
go.the transmission level is reading fine can
you guys help me with the problem I think is
one of the sensors can you tell me if you
familiar with these things.never had a
problem with the transmission I change the
radiator in a lot of the fluid came out of the
line. I brought two quarts of transmission
fluid put in the car it want and reverse went
fine put it in drive it go find . park the car for
2 weeks . and want to drive it it won't go
when I put it and drive .but it go and reverse
.just don't get it