We have a 2017 2.3 EcoBoost Explorer. It has the 6F35 transmission. The factory recommended change is 150,000 miles . The dealer refused to to a drain and fill at 10,000 miles. I did it at 12,000 miles and the factory ATF was dark grey with lots of silver. I changed it 10,000 miles later and again 10,000 miles more later. I bought a case of Mercon LV from Rock Auto for $5/quart delivered. I'm now using Castrol TransMax that's licensed by Ford for the LV fluid, and it's full synthetic, Mercon LV is not. My last change at 27,000 miles of useage came out red with almost nothing on the magnet. Changing the ATF on this vehicle is easier than doing an oil & filter change. The tranny works fine.