904 tranny problems

I checked it in neutral and was full. I have s automatic transmission it goes into each gear fine. I have to rev it high in all gears for the car to move that why I was thinking maybe it could be the brakes. I really appreciate the help guys

If your feeling it drop in forward and reverse solidly it does sound like a brake issue. You might try jacking it up and seeing if you can spin the wheels freely by hand. That'd tell you if a brake was hanging up