Probably the biggest thing you can do to control your speed going downhill in the mountains is by being in a low enough gear. Use your engine brake. It will help to save your other brakes. I rarely use my brakes until I’m almost stopped on ramps etc. City driving that’s not such a great option, but on the highway, and especially in the mountains, it will be your friend.
@Michelle33 -- If you haven't already -- read the following Forum thread (the truth about reefer duty is revealed): Dispatched loads wasting entire day -- L