The pros and cons of manual and automatic transmissions

If you've ever driven a classic sports car, you've probably experienced the thrill of driving a little too fast while enjoying the power of the machine as you engage the clutch and shift the gears. You may have instead been exposed to a manual transmission when you tried learning to drive in your grandfather's old car – and failed miserably trying to start up a hill. You never could quite get the clutch right, could you?

"Only 3.9% of new cars sold in 2013 had manual transmissions."

But if the latter is the case, it should come as a pleasant surprise that, for the better part of the existence of the combustion engine, car makers and gear-heads alike have been trying to perfect the automatic alternative to the classic manual transmission. In fact, Edmunds reported that only 3.9 percent of all new cars sold in 2013 had manual transmissions, and 67 percent of the 2012 models were only available with automatics.

But despite this industry trend, there are some who will always prefer manual to automatic transmissions for a number of reasons. If you're in the market for a used car, it's likely at some point that you'll have the option of choosing which transmission you would prefer, and there are advantages for both. Understanding the pros and cons of the different transmissions will help you make an informed decision when you're looking for a car. But first, a rundown of the mechanical differences:

What is a transmission?
According to How Stuff Works, all engines have what's known as a "red line," which is the maximum rpm an engine can operate at before it explodes. The transmission changes the gear ratio between the drive wheels and the engine so that the engine continues to operate below the red line as speed increases. Manual transmissions have a set number of gears that the driver shifts between depending on speed and rpm. Automatic transmissions, on the other hand, utilize what's called a planetary gear system that allows one set of gears to provide different ratios, according to the source.

The ideal transmission would allow infinitely flexible ratios, allowing the engine to always operate at its best. The continuously variable transmission is a newer form of automatic transmission that seeks to provide this perfect ratio scenario. Advancements in technology have allowed car manufacturers to start incorporating the automatic CVT in newer cars, and that move may help seal the fate of manual transmissions. 
Automatic transmissions utilize a planetary system to maximize available ratios.Automatic transmissions utilize a planetary system to maximize available ratios.

So while this all might sound like a bunch of mechanical jargon, it plays a large part in defining which transmission is actually better. Here are the pros and cons of manual versus automatic transmissions:

Manual pros

  • According to Consumer Reports, manual transmissions can increase mileage by up to 5 mpg in some cases.
  • Vehicles with manual transmissions are often cheaper than automatics by around $1,000. 
  • The New York Daily News reported that manual transmissions are easier to maintain – in general, the clutch is the only part that ever needs to be replaced, and a lot of people would argue that a good driver can make a clutch last a long time. Also, manuals are lubricated with gear oil, which doesn't break down as easily as automatic transmission fluid so it doesn't need to be changed as often, – if at all. 
  • Manual transmissions allow for more control over the vehicle – whereas automatics are constantly pushing the car forward when it's in drive, a manual only responds to the driver. 

Manual cons

  • Manual transmissions are no longer an option for a lot of cars, and are usually limited to small vehicles and sports cars.
  • Driving stick requires more skill than an automatic – it takes practice to learn how to properly use the clutch, and improper use will lead to more wear and tear.
  • Using two feet to drive can be uncomfortable for some people, which also depends on how the car is designed. 
  • Driving in the city is only fun if you truly enjoy driving a stick shift. Stop-and-go traffic can be a real hassle if you're driving a stick, and that kind of shifting can cause excessive wear on the clutch, according to Consumer Reports. 
  • Manuals may be harder to sell down the line, since they are less popular now than ever.

Automatic pros

  • An automatic is far easier to drive than a stick – all you do is put it into drive, reverse, park or neutral. While newer automatic transmissions are incorporating more gear choices, there's still little work to be done on the part of the driver. 
  • Automatics are great for the city – driving in traffic is considerably easier with an automatic, as there is no need to shift constantly with the ebb and flow of traffic.
  • "There are far more options available with automatic transmissions."

    Car Talk pointed out that CVTs are as close as anyone has come to creating the perfect transmission, and their advent is helping automatics exceed manuals in terms of mileage. 

  • As the Edmunds statistics indicated, most manufacturers have significantly cut back on having stick shifts available for their models, so there are far more options available with an automatic. This also means there's a wide variety of used cars with an automatic transmission.

Automatic cons

  • The driver has less control over the performance of an automatic transmission because it does the shifting itself. According to Car Talk, automatics that aren't CVTs create a problem with gear slippage as they get up to higher speeds, hurting gas mileage. 
  • Despite advances in technology with CVTs and gear sensors, most automatic transmissions generally get lower mileage than their manual counterparts.
  • Cars with automatic transmissions are usually more expensive than those with manual transmissions. This is especially true if they are equipped with the latest CVT transmissions which are also the best performing. 
  • Automatic transmissions are very complex machines due to the planetary gear system. If they break, it can cost a fortune to have them fixed or replaced.

So if you consider that manual transmissions only get a few more mpg than automatics, and there are far more cars available with an automatic transmission, that's the way to go. Car Talk even went so far as to conclude, "the only good argument for buying a manual transmission these days is 'Because it's fun.'" 

But it's all up to you, the driver, to figure out what you're most comfortable with. Some people just love driving a stick. Whatever the case, pop into New Jersey State Auto Auction and have a look through their used car selection – chances are you'll find what you're looking for.