I have a 2006 2500HD Duramx with a ZF S6-650 manual transmission. It has 111,500 miles on it and the engine is completely stock. I've been reading up on engine brakes and using the turbo vanes to somehow to act like an engine brake. Any recommendations and is this even possible with this model truck with a manual transmission. For motor reference the VIN is 1GCHK29296E171158.