Okay just to refresh everyone on how to proerly brake in the mountains or any downhill for that matter.
1. put transmission in the gear you would go up that hill in, for 6 speeds and low profile loads go one gear lower, IE if you can pull up that grade at 50 in 4th then put in fourth (or 3rd) This MUST be down before heading downhill!
2. determine your max speed for the hill then when you acheive that apply brakes to bring you to 5mph slower in aprox 5-8 seconds, if you cannot slow down in that time frame you are going too fast, then release brakes completely allow to come back to "set" speed and repeat.
This works with or without ebrake but 2 will not be needed as much with e brake.
If you follow this you will have a much better time driving in the mountains. Have fun and enjoy the power but be sure you have the brakes.
Don't have an ebrake and haven't "needed" it from lessons taught many years ago by father and grandfather. I do beleive in them and will add one in the future or order on the new truck.