Well I just bought a 01 f250 crew cab 4x4 auto. The truck has 313k on it. I have receipts for new injectors all front end work and trans. But on te way home it makes a humming sound under acceleration. Any ideas in what this might be. Doesn't do it when u let out of the throttle and you don't really hear it at crussing speeds. Anything else that I should check with the truck having so many miles? Has no blow by and plenty of power. I was thinking maybe a carrier bearing because I don't think it could be a hub in my expierence with these trucks when a hub starts goin it kicks the 4 wheel drive hub and it doesn't have a abs light on.