2016 3.5 eco . 12,500 miles . Have had no problems until . Was in a hilly area on cruise at around 60 mph . When the truck started going down a fairly steep hill . It was like it jumped out of gear went to around 6000 rpm then down shifted dropped around 2000 rpm down shifted again and went to normal and ran fine for the rest of the trip around 80 miles . Any body have this happen ?

 

The computer will downshift the trans on a downhill as it tries to maintain the set speed without over running but my '17 will also apply brakes on really steep hills. To go to 6 grand on a downshift to hold 60 mph it must have downshifted across a bunch of gears but that is how it behaves.

 

yep, normal. When the cruise control is set, this vehicle will do anything to keep your vehicle at that set speed. So it downshifted to keep the vehicle from going too fast.

On my last truck, an '03 f150, this feature wasn't present. So in that vehicle if I set the cruise at 60, and went down a hill, the vehicle would just accelerate with no downshifting.

 

I had no idea it would apply braking pressure. Good info.

 

Yep, as the others said the truck was trying to downshift to control your speed down a hill.

This has been common for quite awhile...I remember my dad's '01 Grand Caravan was the first vehicle I've seen do this. I can get my little Escape to do this at a certain portion of road every single time.

 

Is the system that applies the brakes part of the "hill descent control" that the fx4 trucks get? Or part of the same system that controls the transmission and down shifting?

 

Nope. Hill descent control is an off-road mode that only functions between 2-20 MPH. It uses the ABS system to maintain speed down a steep hill so the driver can focus on the correct path down said steep hill without losing control. Very different systems.