Not shifting gears properly or at all on 2007 Chevrolet Avalanche

stopped at a stop sign and when tried to drive, couldnt, engine just reved. Had to shift to 1 then work my way up to D. I have to do that everytime now, is the trans gone? does it need some kind of fluid other than trans fluid, that was at the proper level.

there is an internal issue. take it to sa trans shop and let them give you an estimate.

Thank you.