1hdt/a442f 80 series. It's the full hydraulic trams. I posted a thread up on mud too. But here is what's going on. When accelerating, the Trans studders significantly when it shifts between gears. It also starts acting like the torque converter is losing its grip after a few seconds. However I can put the truck into park and turn it off, the turn back on and accelerate slowly with no problems. After it gets up to 55-60 mph it will maintain speed for a couple minutes then "loses grip" and revs up again. Seems like decelerating causes it to "lose grip" too. When it "loses grip" all gears are affected and unable to accelerate in 1,2,3 or 4, motor just revs up. I think that's it but I'm happy to try any suggestions or investigate further questions. ANY help appreciated.