Tranny started erratically, acting badly. Thinking it is limping, but not sure. Some days it will perform normally with an occasional clunky shift, (no specific gear). Other days, it will shift very hard going into forward or reverse and may even stick in, say 3rd and will not shift down at a stop, until I shut engine off and wait a few minutes,,,,, start it up and then works normally for a while. recently pulled our 15,000 horse trailer without any trouble. But when I was very easy on it, it started acting up again. I changed the spin on filter and cut it apart with a tubing cutter for a clean cut, and was like new and the fluid was like new, and not low or burned smelling. A transmission shop checked it out and said it was mechanically fine, but getting bad commands. The EFI Live tuner shop checked it and said the tranny is shot. Who do I believe, as there is no pattern to this Problem. I do not want to spend $4000 if I do not need to.