How Transmissions Work | Manual vs Automatic Transmissions

How Transmissions Work 101 - Manual vs Automatic Transmissions

The debate over manual versus automatic transmissions is largely subjective. As a country of car people, there are many opinions about what makes the best ride. It really depends on what you need and how you want to feel when cruising in your vehicle. Some people describe feeling powerful while driving stick shift, while others find it difficult and appreciate the ease and safety of an automatic.

These days, most people buy a car with an automatic transmission. Manual vehicles, however, have a certain allure to them—images of fast cars roaring along an open road. Or, if you were given your mom’s hand-me-down vehicle as a teenager, manual cars can remind us of learning to shift, but mostly stalling, in an empty parking lot.

Why are manufacturers and consumers ditching the manual for automatic? What are the key differences between the two? We explore the manual vs. automatic debate.

Manual vs Automatic Transmissions

Almost all car manufacturers offered a choice between automatic and manual drive trains. Many consumers preferred manual transmissions because they ran up to $1,000 cheaper and usually got better fuel efficiency.

As the years went on, however, car makers were able to make the automatic transmission better and drivers began to get used to the ease of automatic shifting. As the advantages began tipping in automatic’s favor, they became the preferred choice. Sales went up and manufacturers started to save money by only offering one drive train option.

For young people, knowing how to drive a manual transmission is nearly unheard of. Driving schools that offer instructions on manual transmissions are rare. That’s unfortunate because there are still many reasons to choose a manual transmission.

One thing to keep in mind, however, is resale value. According to a report from U.S. News and World Report, only 18% of Americans know how to drive a stick shift. This limits your pool of buyers when looking to sell your car or trade for a new one.

Click here if you want to learn how to drive a manual transmission.

The Basics of How Transmissions Work

A car transmission uses the ancient concept of a lever, in the form of gears and gear trains, to provide speed and torque conversions, which is applied to power your vehicle. Transmissions are used in mechanical engineering to improve mechanical efficiency and make the most use of an engine’s torque.

A gear is basically a collection of levers that rotates. Larger gears take longer for a full rotation, but provide greater force. The transmission, composed of many interlocking gears (levers), is located right underneath the gear shifter.

Here are some of the gears that you shift in your motorcar:

  • The Engine Shaft comes from the engine
  • The Drive Shaft carries the power to the rear wheels.
  • The Countershaft connects the Engine Shaft to the Drive Shaft.

The main difference between manual and automatic transmissions is that the manual transmission uses multiple sets of gears to the drive shaft while an automatic transmission uses a planetary gear set to produce different gear ratios.

The drive shaft going to the wheels is in mesh with another gear on the countershaft. These gears, also called dog teeth, are always in mesh and turning when the engine is running.

The clutch sleeve cannot turn on the drive shaft but is free to slide back and forth. On the sleeve, a large gear is mounted that can move from the drive shaft to the engine shaft. The sleeve gear can move in order to create different gears for higher or lower speeds.

A large vehicle takes a large amount of force to start. The power goes through the gears in the transmission. The gears help regulate the power for maximum efficiency.

Here’s a problem: An automobile must be able to go backward and forward so another set of gears is added, called reverse idler gears. The power travels through the transmission. Now, there are multiple sets of gears for going forward and another set for going in reverse. Noise and wear are common.

What’s the Difference? Transmissions 101

Your car’s internal combustion engine creates power and torque, but it is only really useful during a certain speed range. Instead of connecting the drive wheel directly to the engine, the transmission, or gear box, controls the engine’s speed and torque (RPM).

The transmission makes sure the engine’s RPM is always within the maximum efficiency range, taking care of the speed variations in the drive wheel.

A manual transmission, also known as a stick-shift, requires the driver to use a stick to change gears. Manual transmissions are based on a collection of simple gear pairs and uses a clutch pack.

Automatic transmissions are based upon a planetary gear set and uses a torque converter. An automatic transmission shifts the gears on its own.

Comparing the Benefits

1. Fuel Economy

Fans of the manual transmission always boast of greater efficiency and fuel economy. In the past, this would have been true nearly every time. But as technology improves and automatic transmissions get better, you are starting to see the automatic version beat out the manual version in terms of fuel economy.

2. Price

Manual transmissions are cheaper to install and the sticker price reflects that. However, if you do not know how to drive a manual vehicle and aren’t looking for that type of driving experience, then the generally lower cost isn’t helpful.

3. Options

Although fewer and fewer cars with manual transmissions are made each year, there is a wide variety to choose from, including trucks, sedans and sports cars. Automatic vehicles are the new norm. Every company will provide you with several automatic options with modern technology and safety features to encourage that smooth ride.

How to Choose: What to Consider Before Purchasing

Before purchasing a manual or automatic vehicle, there are some basics to consider:

  • Know the Difference – Don’t go into the purchase blindly. If you don’t know the difference between the two types of transmissions, from maintenance to function, do some research or speak to someone with experience with cars.
  • Power & Acceleration – Manual transmissions tend to have faster acceleration, but it depends on your needs. An automatic transmission is conventionally a 4 or 5-speed, while a manual transmission is a 5 or 6-speed. If you’re looking for that ultimate speed and performance, a manual gearbox is generally the go to.
  • Semi-Automatic – If you are having trouble deciding, semi-automatic is an option. This is mainly found in sports cars. You have an automatic transmission with the option to switch over to a manual mode.
  • Mileage & Fuel Economy – Based on how much you use your vehicle, you will want to consider which transmission gets the best mileage. EPA ratings can help you research and compare different brands before purchasing.
  • Repair – Every car at some point will need repair. What’s the difference in cost between the two transmissions? In general, and you may not have thought this, but manual vehicles are often cheaper to maintain and repair. However, something like a clutch replacement is costly and does need to be replaced on occasion in manual transmissions.

Auto Simple is your source for both manual and automatic vehicles. We can offer support in your search for a new vehicle, and provide the information you need to make the best decision for you and your daily needs.

Stop by any of our locations for the best deals on used vehicles:

Chattanooga, TN – (423) 551-3600

Cleveland, TN – (423) 476-4600

Dayton, TN – (423) 775-4600

Dalton, GA – (706) 217-CARS (2277)

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