monkid101

My 2017 f-150 revs up several hundred RPM's while going down hill in the mountains when in low range 4x4.. I have 4 miles of rough road, which requires low range 4x4 to get to hunting cabin..... When leaving cabin, its all down hill..... While in 2 gear, low range 4x4 everything works really well holding back,, then all at one the engine revs up and goes to 2500 rpm, which requires braking to slow down..... after slow down, it will hold back great for several hundred feet.... then takes off again..... It acts like the torque converter disengages or it kicks itself into neutral..... I have tried turning off defrost, which lets air conditioner come on and off while engaged,,,, that dont work, still revs up.... anyone have this problem??? All my other trucks come out of mountain very well in 2nd gear and never had to brake,,, usually had to give gas to get over water breaks in road...... Yes I have hill descent ,, but all that does is brake when you dont want it to and gets brake warm coming out of mountain,,,, any solutions..................... Truck has done this since it was new,, so nothing is dirty in air boxes.................. Thanks, Bob

PerryB

I don't know the answer (sorry) but this is not the first thread I've seen about the issue. It was being discussed here several months ago. If I can find it, I'll link the thread.