F350 Super Duty vs 3500 Denali vs The Ike Pulling 30k lbs

4x4ord, I know for sure that my truck does not apply the service brakes and I don't think Ron's truck does either but we'll see what his reply is. I know that for my truck it is rare that I need to use the service brakes towing my fiver in the steep mountain grades in BC as long as I'm in the right gear, which is usually 3rd in my G56 manual transmission. This is 1 gear lower than I climb tough grades in. I leave my exhaust brake on the FULL setting all the time, and don't use the variable setting.