hello,
I have a freightliner truck that we pull doubles with. first off we changed the oil psi sending sensor. after it was replaced I sent it out for a load and the truck would not do more than 54 MPH empty. brought it back did and oil and filter change as well as a fuel filter change. we felt it might be the dump gate on the turbo so we replaced the entire turbo. when we test it with just the tractor it does its governed speed, when we put a set of empty trailers on it, it struggles to get to 54 MPH. unsure of what it could be. any help would be appreciated.