Congratulations on starting your driving adventures—I’m sure you’ll do great! 4D just means fourth gear, and the D indicates that this is the gear for overdrive. In other words, this is where you’ll set an automatic car for pretty much all driving, and it’s where you’ll end up after moving through the gears in a four-speed manual transmission.
4D shouldn’t be confused with 4WD, which stands for 4-wheel-drive and is a whole other animal.
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