How Does an Automatic Transmission Work?

In this brief article brought to you by Wrights Car Care, we dip our toes into the fascinating world of automatic transmissions in a way that's easy to grasp. If you have any questions or are looking for a reputable auto repair shop, then give Wrights Car Care a call or visit. Our team is on standby to help.

What is an automatic transmission?

A transmission is a mechanical system in a vehicle that transfers power from the engine to the wheels, allowing the car to move and shift gears. An automatic transmission is a type of transmission that changes gear ratios automatically as the vehicle moves. This frees the driver from having to shift gears manually. These transmissions make driving more convenient, especially in heavy traffic where frequent gear changes are needed.

The Basics: Primary components of an automatic transmission

At its core, an automatic transmission uses a combination of gears and a special fluid to transfer power from the engine to the wheels. Let’s take a closer look at the primary components:

• Gear Sets: The heart of an automatic transmission is the planetary gear set, which is made up of a sun gear, planet gears, and a ring gear. These gears work together to provide different gear ratios.
• Transmission Fluid: This special fluid lubricates the moving parts, cools the transmission, and transmits power. It’s essential for a smooth operation.
• Torque Converter: Instead of a clutch (which you’d find in a manual transmission), an automatic transmission has a torque converter. This allows the engine to keep running even while the car is stopped, and it smoothly transfers power from the engine to the transmission.
• Valve Body: This is the control center of the transmission. It directs the flow of transmission fluid to select the correct gear.
• Bands and Clutches: These parts engage and disengage gears in the planetary gear set, controlled by hydraulic pressure from the transmission fluid.
• Transmission Control Unit (TCU): Modern automatic transmissions are connected to a computer. The TCU monitors the vehicle’s speed, throttle position, and other factors to determine the best time to shift gears.

How does an automatic transmission work?

When you start your car and put it into drive, the transmission is usually in first gear. The torque converter connects the engine to the transmission, allowing power to flow through.

As you accelerate, the transmission fluid flows through valves in the valve body and creates hydraulic pressure. This pressure moves the bands and clutches that engage different gears in the planetary gear set. The car shifts to higher gears as you speed up, all without any additional input from you.

Once you reach your desired speed, the transmission maintains the appropriate gear. The transmission fluid continues to cool and lubricate the system.

When you slow down, the transmission automatically downshifts to a lower gear. Here, the torque converter again plays a crucial role by ensuring the engine doesn’t stall when the car comes to a stop.

Caring for your automatic transmission.

All vehicles require maintenance, but automatic transmissions typically require more maintenance than manual transmissions due to their complexity and the reliance on transmission fluid. Neglecting maintenance can have you pulling up for auto repair service more often than necessary.

Perhaps the most important thing is to make sure the transmission fluid is at the proper level; and remember to have a mechanic inspect and service the transmission periodically. Residents in the area can call Wrights Car Care to schedule a convenient appointment or arrange urgent service for as soon as possible.