It might get better with a bit of exercise, but it may also be that the seals need to be replaced. A rebuild with mainly seals & gaskets shouldn't be too bad. If you were down here I'd say take it by my local tranny shop and ask Paul what it needs to be right. I agree with Mike that the AOD would be hard to beat in the truck. Just keep it out of OD if you're pulling a trailer/loaded heavy.