When I get to 60 miles an hour the engine looses power. If i back off abit it will catch up and let me accelerate some. If I don't back off the engine will die. Once I pull over and stop it restarts easily. Any thoughts?

Have you thought of a fuel flow problem rather than a transmission problem? Sounds to me your engine is being starved, have you changed the fuel filter or checked the pump? You may have a vacuum hose leaking that can have the same result or it could be injector issues
It’s a start but there is not enough information to allow me to give you something more definit.