I have looked up this code and see it is an internal transmission code! My brothers truck is throwing this code and needed a lot of throttle to take off! His is an 03 auto 2500 with a standard output engine. The oil is a little dark in color but not burnt smelling. Does anyone know or have any ideas what can be going on?????

 

Doesn't look like anyone has any pearls of wisdom on this one little buddy.
He may have to take it to the dealership or a transmission place for some diagnostics. Hopefully it wont be $$$$.