94 cherokee tranny problems

I'm new to the whole automotive world, only 20yrs old and didn't have much education on it growing up. Love cars and trucks, got a 94 Cherokee lifted on 32's when I was 18, loved it til it started to breakdown. Have had everything fixed by a pro til I ran out of money. Just had a new motor put in and still owe money on it. Now my auto tranny started acting funny. When I'm taking off in drive, it will often rev really high as if in neutral until it catches first, then will still do it when I go over bumps in lower gears (first or 2nd) once I hit 3rd, it doesn't slip, but it also doesn't want to take overdrive. Had to feather my gas pedal til it would take OD, then as soon as I try to accelerate, boom it slips into 3rd immediately. Stays in 3rd no matter how fast I'm going. Any ideas??