Hi all:

I am new to this group and this is my first post. (I own a 2000 Ford
explorer sport with the most basic no frill engine.)
Here the very newbie question: What purpose does the O/D serve?
Should I leave it on or off?
Someone told me that leaving the O/D on was essential for highway
driving but a waste of fuel for city driving. Is this true?
Does anyone actually know how the O/D works? Txs.