Transmissions

Different types of transmissions and how they work

In Uncategorized by HomeTowne Auto Repair & Tire

Transmissions transfer power to the wheels from the engine. They determine the force and speed based on where and how the vehicle is being driven.

There are a few different kinds of transmissions used today – manual transmissions, automatic transmissions, continuously variable transmissions (CVT) and automated manual transmissions (AMT).

Each type differs in its design, operation and components.

Manual transmissions

Manual transmissions consist of an input shaft, intermediate shaft and output shaft. 

The input and output shafts are each connected with the intermediate shaft.

There are also several gears that enable us to travel at various speeds, with lower gears used for slower speeds and top gears operating at faster speeds.

Because the gears aren’t attached to the output shaft, a hub and sleeve are needed to link them as you shift. In order to switch, the clutch must be disengaged.

It has a manual clutch where you press the pedal to disengage the transmission.

Automatic transmissions

Automatic transmissions use a planetary gearset, which is made up of an output and two inputs. As the input speeds change so does the output speed.

The output of another planetary set connects with an input of the first one.

This system also has two clutch packs, which prevent the ring gears from moving. While switching gears, the clutch pack is pressed. The ring gear stops while the carrier turns.

The output speed can rise if the ring gear is able to move. This is possible by letting go of the first clutch while simultaneously connecting with the second clutch. The ring gear then links to the carrier of the other planetary set.

An automatic transmission has a torque converter that connects the engine to the transmission, which allows a certain amount of slippage so you don’t need to push in a clutch pedal when you come to a stop.

There’s a valve body that is electronically and hydraulically controlled to change the shift points, depending on how the vehicle’s being driven.


Continuously Variable Transmissions (CVT)

A Continuously Variable Transmission (CVT) is an automatic transmission that offers various perks, such as less carbon dioxide emissions and fuel consumption.

This system consists of a couple of sheathes that are located on drive and driven shafts. Between them, sits a metal push belt. 

One of the sheathes is able to move on the shaft, allowing the transmission ratio to shift automatically and continuously.

CVT components team up with an electronic system. Together, they provide a good torque and RPM ratio.

Automated Manual Transmissions (AMT)

If your vehicle has an Automated Manual Transmission (AMT), you are able to shift manually or automatically. 

When you choose the automatic option, the gear adjusts on its own.

An AMT uses several parts – change lever unit, clutch actuator, gear shift unit and transmission control unit.

The change lever unit allows you to go from neutral to drive. When you shift gears, a signal is sent to the clutch actuator and gear shift unit by the transmission control unit. 

The system chooses the correct gear needed, which decreases damage to the clutch and improves fuel economy.

With this transmission, you get the best of both worlds of a manual and an automatic transmission.

Maintaining your transmission

One way to take care of your transmission is through transmission fluid exchanges, which we recommend every 30,000 miles. The intervals also depend on the vehicle and what the manufacturer suggests.

Overtime, contaminants build up in the transmission fluid that acts as a lubricant. This can cause valves and solenoids to stick and parts to break down.

Transmission fluid exchanges help components last longer.

Some transmissions have a filter. You don’t have to necessarily change the filter during a fluid exchange, especially if they’re performed early on and through the life of the vehicle.

The filter acts like the air filter for your house. It filters out large contaminants that would normally go through the transmission. Depending on the car’s mileage and age it might be a good idea to also change the filter.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.