When to change/flush transmission fluid on 2017 Ford Explorer Sport? Maintenance schedule says 150k miles, dealer suggest at 40k miles. Big difference.

I would do a drain and fill at 40K not a full flush.

The guy who does my transmission work recommends 40K for the first change with filter and 40K intervals after that. He states the transmission is electronic and full of solenoids which can foul if contaminated with metal shavings. One solenoid cannot be changed, meaning the entire valve body must be replaced in any solenoid goes out.

Filter cannot be replaced unless transmission is removed and split in half. Heavy on labor costs. 40 K drain and fill will keep it in good shape