What Is The Difference Between 10, 13, and 18 Speed Transmissions?

Truck driving is more than just sitting and following a map. Driving a diesel truck takes experience and a lot of concentration. You have to watch the road as well as the other drivers. You also need to know your gears. Not every truck has the same number of gears and drivers have to know how to shift the different speed transmissions.

The most common transmission in trucks today are 10, 13, and 18 speed. There use to be trucks with a 15 speed transmission back in the 1970’s but 18-speed replaced it because it was easier to shift. So what is the difference between 10, 13, and 18 speed transmission? How do you drive and shift an 18-wheeler? I am not an experienced truck driver but here are the basics in the different transmissions.

What Are The Differences


10, 13, and 18 speed transmissions refer to the number of gears each manual transmission has. So a truck driver with a rig that has a 10-speed transmission will have to go through 10 different gears. The shifter does not necessarily have ten different slots to be shifted into. The basic shift pattern for any truck is in the form of an H.

All the gears are broken down into hi gears and low gears. So the 1st gear will have both a low gear and a high gear. You start out in the low and then switch to high. This applies to both the 13 and 18 speed transmissions.

The reason for different gears is for different toque and pulling power. The more gears you have, the bigger the engine and the more power. In an engine like and 18-speed transmission, the gears are close together. That means that each gear is another small increment of added power. It is not a big jump between each gear. A truck with fewer gears means that the steps between each gear are bigger.

What this boils down to is when you have a transmission with large gaps between each gear, you have to run your RPMs higher before you can shift. Having gears that are closer together saves time and is more fuel efficient. Having more gears gives you more options when hauling. You may have an 18-speed transmission but if you don’t have to go through all of the gears. You can use it like a 13-speed and skip some gears.

How Do You Drive an 18-Wheeler

Basically, an eighteen wheeler is a nine speed with nine auxiliary gears. With an 18-speed transmission, the gear shift has two switches. One switch is for high and low versions of each gear and the other switch is for Direct Drive and Over Drive. You can flip the switches back and forth to go through each gear. You start out in 1st gear low and flip the switch to 1st gear high. Then you shift gears and go to 2nd low before flipping the switch and going to 2nd high. You can go through the lower gears normally by not flipping the switch but only if you are not loaded heavily. If you want to learn how to properly drive a big rig, you need to go to truck driving school and get certified to take your driver’s test.