F53 engine rpm on steep downgrade

[chasfenwick]

We had just entered a steep downgrade on the Interstate when engine rpm went to exactly 4000 and stayed there. 60 mph. Tried slowing to 50 mph via braking and it had no effect on rpm. Was hesitant to change transmission selector to N or 4. I don't like to see something as high as 4000 rpm for very long, and had never seen this before. Cruise control OFF. Was this normal behavior for the F53? Should I have done something other than being a concerned bystander? I notice that there is no "red line" on the tach . . .

2017 Precept 31UL.

[Mustang65]

As far as the lack of a Red Line on the Tach, if it is like our EcoBoost it has a Rev Limiter built in, so it cares for the RPM's on its own. No idea as to whey the RPM's did not come down while braking. I never did 60 in the steep downgrades in CO, kept it around 45, a lot safer and a lot easier to stop the heavy load should I need to. Same as the big trucks. We have a tow haul mode, not sure if you have one, that automatically cares for the downshifting, cruise control does the same.

Don


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[chasfenwick]

Oh, I should mention that this chassis DOES have a tow haul mode available, so activating that is something else I could have done. Just wasn't sure what the effect might be . . .

The fact that the revs went to exactly 4000 and stayed there makes me think that that must be the automatic limit that is built in to the control system.

[Marcm157]

My 16 F250 gasser does that somewhat regularly but only when in tow / haul mode. It seems it is activated by a double pump of my brake pedal but it only does it when I am in Tow/Haul mode.

[Mustang65]

What I normally do is before I get to the steep incline (down) usually have yellow warning signs, I set the cruise control (with tow-haul mode on) to 8 MPH below the speed you want to go and your speed will be right around where you want to be. Your setting may be a little different.

Don

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