Ultrashift 10 speed auto sometimes won't go into gear

2011 peterbuilt Cummins Easton 10 speed ultra shift.
have similar problem took it in got charge 6k new cluth and other things change still did the same change out position censor fix it for a bit I think then it did it again what could it be ?run good only when you switch from neutral to Drive or reverse it mark its in but won't go play with it N to D eventually you feel it catch on what could it be