Jake Braking A 5er Down Long Steep Incline

Cummins12V98 wrote:
I gave the "AUTO" mode a shot. I was descending I-15 to I-215 from Barstow, I would guess it's 5-6% grade. I let off and tapped my brakes at 60 mph. It only took seconds for my speed to increase to 70. I hit the brakes and set cruise to 55 and locked in 4th. I adjusted the cruise up and down to stick close to 60.

Lighter loads may work on AUTO but 35k combined is No Bueno.

If you think about what auto EB is doing you’ll better know how to use it. Auto EB on the Ram is capable of producing exactly the same back pressure as “full on” EB which is 60 psi. The amount of braking the EB can do is a function of the back pressure x the engine rpm. If you let off the throttle at 60 mph the auto EB would have closed and been creating 60 psi back pressure. If the truck starts slowing down the auto EB would open to prevent slowing dow … it’s trying to maintain the speed you were travelling when you let go of the brake. As soon as the truck started accelerating it should have been apparent that the EB could not hold your rig back at the rpm the engine was turning. You could have locked out 6th and 5th gear. If it couldn’t hold back in fourth you could have slowed down enough to lock out 4th gear. If your truck holds back your rig in 4th gear using cc but won’t hold back your rig in 4th gear using auto EB it is because cc is applying your wheel brakes. On the Ford, auto EB will not apply the wheel brakes until the engine rpm reaches the red line…. The Ford cruise control will apply the wheel brakes shortly after the truck accelerates above the travel speed set point.