What Is Manual Transmission?- Definition And Working

Before we start, a moment of silence for the stick-shift-equipped models we’ve lost recently. Chances are the manual transmission won’t be with us much longer. It’s a dying breed.

But don’t have your left foot removed just yet: there are still new cars available in the United States with a manual gearbox. (A handful of SUVs come with them too, but we covered those in a separate list.) If you’re after a row-it-yourself driving experience, one of these cars should do the job.

What is Manual Transmission?

Basically, a manual transmission is a gear box that enables the driver to choose between different gear ratios to drive the car. Lower gear ratios offer more torque, but less speed, while higher gear ratios offer less torque, but higher speed. Different gear ratios are often referred to as “speeds,” so a “six-speed” manual transmission has six forward gear ratios.

At its simplest, the manual transmission consists of three shafts with constantly-intermeshed gears of different sizes. The input shaft connects to the engine, via the clutch. The countershaft is constantly meshed with the input shaft and has multiple gears.

The output shaft connects the countershaft to the driveshaft and eventually the wheels. In four-wheel drive and all-wheel drive vehicles, the output shaft connects to the transfer case first. Reverse gear is usually on a fourth shaft to effect a change in direction.

The gears themselves are not fixed to the output shaft, but freewheel. Locking collars, on the other hand, rotate with the output shaft and can shift or slide back and forth to engage one of the gears. That’s why we call it “shifting” gears.

In “neutral,” with no gear selected and the clutch released, the input shaft and countershaft are spinning, as are the output shaft gears, but the output shaft doesn’t move because none of the locking collars are engaged.

Related Post: What Is Transmission In A Car?- Types And Working

Manual Transmission

How Does a Manual Transmission Work?

To effect a gear change, selecting first gear, for example, the driver depresses the clutch, disengaging the input shaft. Using the shift lever, the driver selects first gear, and the linkage moves the shift fork to connect the 1st-2nd locking collar with 1st gear, locking it to the output shaft.

Now, when the clutch is released, engaging the input shaft, the output shaft turns because 1st gear is locked to the output shaft by the locking collar.

As the driver speeds up, selecting 2nd gear simply involved repeating the process, but moving the shift lever to 2nd gear. The shift shaft moves the shift fork to disengage 1st gear and engage 2nd gear.

Releasing the clutch engages the input shaft again, this time routing power through 2nd gear. Changing to 3rd gear involves using a second shift linkage, shift fork, and locking collar, this one between 3rd and 4th gears.

Because the countershaft and output shaft turn at different speeds, moving from 1st to 2nd gear, trying to engage a higher gear while the vehicle is moving slower would be like trying to turn the shaft at two different speeds, which is impossible.

Synchronizer rings are like tiny clutches, using friction to bring the locking collar and the gear to the same speed, at which point they easily mesh and power can be reapplied.

Types of Manual Transmissions

The following are various types of manual transmissions.

#1. Dual-Clutch.

This transmission uses two clutches, which can be wet or dry. One clutch operates the even gears (2, 4, and 6). The other clutch operates the odd gears (1, 3, 5, and reverse). Dual-clutch transmissions were common in older cars and are still found in modern race cars.

With today’s dual-clutch automated manual transmissions, sometimes called double-clutch transmissions or twin-clutch transmissions, a computer controls the clutch engagement and shifting, bridging the gap between a manual and automatic transmission.

#2. Unsynchronized.

The first manual transmissions were unsynchronized, or “non-synchro.” They were also called rock crushers because drivers would grind the gears together trying to get them to mesh. Trucks used this type of transmission well into the early 1960s because these transmissions were very strong.

#3. Synchronized/Constant Mesh.

Synchronized/constant-mesh transmissions keep the cluster gear, drive gear, and main shaft gears constantly moving. These types of transmission use pads to slow down the gears. This eliminates the need for double-clutching action.

#4. Automated.

An automated transmission sometimes referred to as an AMT, is a manual transmission with a computer controlling the shifting and clutch. The AMT is used in heavy-duty trucks.

#5. Single-Clutch.

Single-clutch is a manual transmission with the computer controlling the shifting and clutch. Shifting and clutch control can be electric, hydraulic, or electrohydraulic. The popularity of single-clutch transmissions started to fade as dual-clutches were able to handle increased torque.

#6. Preselector.

A preselector was a manual transmission with a vacuum or hydraulic shift control that was mostly used in the 1930s through the early 1950s. Some preselectors used bands and planetary gears. Basically, whatever forward gear was selected, the next time the clutch was engaged, it shifted to that gear.

How to Care for Your Manual Transmission

While there are a lot of things you can do to harm your stick shift, there are also a lot of ways to care for it, too. Below are a few manual transmission maintenance and care tips you should know about:

#1. Schedule Regular Maintenance.

It’s a good practice to regularly check and do maintenance on your transmission. Because service intervals vary, you should first check your owner’s manual for the recommended frequency of your manual transmission maintenance. Below are a couple of things you should remember to check when you do your scheduled transmission maintenance:

  • Check your transmission fluid– If you have low transmission fluid, you may have a leak somewhere in your system. When this happens, you’ll need to have your vehicle checked immediately, as this situation may lead to transmission failure.
  • Flush the transmission fluid– While checking transmission fluid levels, you should also check the state of your transmission fluid. The color should be a bright, clear red with a slightly sweet smell. If you notice the color going darker or if there are visible particles suspended in the fluid, it’s time to flush your transmission fluid. Check your owner’s manual for the correct interval and for the right type of transmission fluid you should use.
  • Regularly change transmission filter (if applicable)– Some older vehicles have transmission filters that need to be replaced every time you flush your transmission fluid. You can consult your owner’s manual if you’re unsure whether you have one or not.

#2. Properly Engage the Clutch.

Make sure to properly press down and engage the clutch when you’re shifting gears. This allows your transmission to shift gears smoothly, and it also lessens the risk of damage to other transmission components.

#3. Shift to Neutral at a Traffic Light.

As mentioned above, you risk damaging your transmission if you keep your gears engaged while your vehicle is stopped. Remember to shift to neutral when you’re at a traffic light or when you’re not moving.

Knowing how to drive a stick shift is a valuable skill nowadays. That’s why you should learn how to take care of your vehicle. If you’re interested in learning more about transmissions, you can check our short course on transmissions here.

Advantages of manual transmission

Stick shift vehicles can be a blast to drive, especially for those who have experience with controlling manual transmissions. Nevertheless, there are plenty of other good reasons for having them around:

  • Manual transmission cars are usually easier to maintain than their automatic counterparts. For starters, most manual transmissions tend to be less complex than automatics, meaning that fewer things go wrong in the first place. The only repair item frequently seen is the clutch and that component usually doesn’t require changing until you’ve driven hundreds of thousands of miles, under ideal conditions.
  • Manual transmissions use gear oil or engine oil, in most cases. Unlike automatic transmission fluid (ATF), it doesn’t deteriorate as quickly over time and it doesn’t need frequent changes. Some manufacturers even suggest that manual transmission car fluids don’t need changing unless there’s a leak or after repairs have been completed.
  • Fuel economy is usually much better. Parasitic power losses from the torque converter and hydraulic pump can rob an automatic-equipped car of a small percentage of its power, along with its fuel efficiency. Depending on driving style and road conditions, drivers can increase their fuel economy by as much as 15 percent.
  • Driving one of these gives you a better sense of control over your vehicle. Without the torque converter constantly pushing you forward, you’ll have an easier time with braking. You’ll also have a much easier time with engine braking or using the momentum of the engine itself to slow yourself down.

Disadvantages of manual transmission

Of course, there are few disadvantages to driving a stick shift, as well.

  • Learning how to operate one comes with a pretty steep learning curve. Newcomers can expect to jerk, buck, stall and miss gear changes as they figure out the clutch, timing and other basics.
  • Unlike in an automatic vehicle, starting off on hilly areas from being slightly inconvenient to being absolutely terrifying, depending on your driving skill. Many drivers have rolled back into traffic or stalled out after trying (and failing) to pull away from a hill.
  • Depressing the clutch pedal is a way of life, but the experience can be a bit more painful with heavy clutch pedal feedback. Over time, it can definitely mess with your left leg, especially at the joints.
  • Driving in heavy traffic can be a real drag, since you’ll constantly be engaging your clutch. First-time car owners, as well as seasoned motorists, may find this a real struggle.

Things to Consider When Driving a Standard Manual Transmission

Below are five suggestions to help you extend the life of your manual transmission and avoid breakdowns:

  • Never use the clutch to keep your automobile on a slope.
  • When the engine is running slowly, don’t floor it.
  • In Neutral, you should never coast downhill.
  • Avoid driving with the clutch halfway down
  • Never let go of the clutch too quickly
  • The clutch paddle should not be touched with your left foot
  • Don’t leave your automobile in gear at a stoplight.
  • When parked, never leave your vehicle in neutral
  • When braking, always lower the clutch
  • Never jiggle the gears.

Who Should Consider a Manual Transmission?

If you want to learn how to drive a stick shift, the best way to do it is to buy a manual transmission car. Getting a friend to loan you their car for practice can be tricky, and if you’re only able to drive a manual car every now and then, it will take a while to adapt. With daily practice, you should be able to get the hang of it pretty quickly, especially if you already know how to drive.

Of course, if you already know how to drive a manual, you don’t have to worry about buying a stick shift. Just because automatic vehicles have improved over the years doesn’t mean that manual transmissions have worsened.

In fact, some newer vehicles have benefitted from improving technology. For instance, some have a hill-hold feature that keeps you from rolling in neutral, even if you aren’t braking. Others have an indicator on the dashboard that tells you when to shift gears, which can be helpful if you have kids or friends you plan on teaching how to drive stick.

Finally, auto enthusiasts should consider getting a good manual transmission car to enhance their driving experience and gain some cultural cache among their fellow car buffs.

This is especially true if you’re a member of a drivers club and have an opportunity to take your vehicle out on the track and see what it can do. Performance cars are more likely than other types of vehicles to come with a manual transmission, so if you’re in the market for one, you’ll have plenty of options to choose from.