How Does a Truck Transmission Work?

by Jackson Lewis

How Transmissions Work

Transmissions were developed in order to permit the gear ratio that exists between the vehicle engine and wheels to change when slowing down or speeding up. Gears have to be shifted in order to avoid not only overworking the engine, but also to maintain it running at optimal RPM for performance. There are several types of manual and automatic transmissions that are used in trucks. For all of the varieties of transmission, they are connected to the vehicle engine by the clutch. The clutch allows the transmission to be decoupled from the engine when changing gears in the vehicle.

Types of Transmission

There are two fundamental types of vehicle transmission: unsynchronized and synchronized. The unsynchronized transmission has a number of gears, and normally a reverse gear. In the unsyncrhonized transmission, gears are shifted by engaging and dis-engaging the clutch. This type of transmission is popular for large trucks, machinery and race cars. It has the benefits of being a simpler design which ultimately increases reliability and costs less for repairs over the long term. For large trucks, there is an added benefit of a significant reduction in weight, which allows greater cargo to be carried. Synchronized transmissions, on the other hand, are different in that the gears are always meshed together in the gear box, requiring less effort to shift gears. The clutch in the synchronized transmission is typically made of brass and is used to match speeds of the gears before locking in the change in gear.

How Truck Transmissions Work

There are two types of trucks. First is the type that one uses for recreational use. These use transmissions very similar to car transmissions, having up to six gears, and can either be automatic or manual. Large or heavy trucks have three types of transmissions: range, splitter and range- splitter. The range transmission is similar to that used for smaller trucks, but it has a high-low gear split which allows reuse of the same gear shift positions for gears in low and high mode. The splitter transmission also uses a high-low division. Instead of having a high and low section, the gears are split into two so that each position of the gear shift is used for two gears (one high and one low). The range-splitter transmission is a combination of these two setups allowing for greater gear positions and selections.

About the Author

Based in Memphis, Jackson Lewis has been writing on technology-related material for 10 years with a recent emphasis on golf and other sports. He has been freelance writing for Demand Media since 2008. Lewis holds a Master of Science in computer science from the United States Naval Postgraduate School.

Photo Credits

  • photo_camera GM Truck Transmission