Many of us grew up with automatic transmissions and never took the time to learn to drive a stick shift (manual transmission). Perhaps we find it easier, especially when driving in the city where there are frequent stops and starts. Others love the visceral feel of shifting the car manually. Aside from the personal preference aspect, though. What are the real differences between automatic and manual transmissions from a technical standpoint?
The transmission converts the power of the engine to the drive wheels. It uses a gearing system to transfer that energy as efficiently as possible. An automatic transmission switches gears as the car accelerates or decelerates without the driver taking any action. Manual transmissions, of course, require the driver to depress the clutch, move the shifting lever to the desired position, and then release the clutch in order to change gears.
First, a car or truck with a manual transmission will tend to get 3-5 miles per gallon better gas mileage than the same vehicle with an automatic transmission. That can amount to a significant savings over the life of the vehicle, but there is a caveat. You'll only get that better mileage if you are experienced with the manually shifting. Shifting too quickly or too slowly while accelerating can erase that extra gas mileage in a hurry.
Another plus for manual transmissions is that they are less complex internally than automatics and you might be able to shave a little bit off the price of a new vehicle by choosing a manual over an automatic. The simplicity of the manual transmission also makes it easier and, therefore, cheaper to repair if there's a major problem. That repair cost, may be partially offset by the fact that the automatic will never need a new clutch, because it doesn't have one. The clutch in a manual transmission vehicle may wear out over time and need repair or servicing eventually although this may not happen for many years after the vehicle hits the road.