RE: Operating the “tow/on” going down a 4-6 mile-6% grade.
Slowing at the top of incline, I push “tow/on” to take us out of overdrive (5th gr) & begin decent. Big Bird (BB-our 2016, 35 US) met 3 conditions (acceleration, minimal or no throttle, & an undefined period of time) described in OM. System shifts to next lower gear making huge increase in decibel level & hits 4200 RPM. This with periodic breaking is followed by break-cooling periods. Fearing the next downshift would again increase RPM, I take BB out of “tow/on” after a short time.
Called Ford. QUES: With no yellow or redline on the Tach, what is “redline” and set expectations of operating syst.
ANS: Redline = 5260 RPM. Tech indicates BB will up-shift to prevent over-revving & will NOT downshift into a damaging condition; 4200 RPM will NOT damage the engine during descent, regardless of how disturbing it sounds in the cockpit or the length of time @ 4200 RPM to get to the bottom.
Chris
Big Bird