How an A4LD Transmission Works

Automobiles operate using internal combustion engines for power. In an internal combustion engine, a mix of fuel and air is ignited by a spark provided by spark plugs. The ignition takes place inside a combustion chamber called a cylinder. The resultant force pushes the piston out of the end of the cylinder and provides mechanical energy to the engine. The transmission is the portion of the automobile that transfers the power of the engine to the drive shaft. Engaging the gears in the transmission allows the car to move, and disengaging the transmission allows the car to run without moving, also known as idling.

The engine of a car requires the use of a transmission to enable different gears for different speeds. When the car has different speed or load requirements, it has different power needs. If the car only had one gear available, it would require the most power available, which is not compatible with many situations.The car cannot perform as well without being in the correct gear, aligning the correct gear configuration with the needs of the car. To perform with the most efficiency, there must be multiple configurations available. Automatic transmissions accomplish this process without the need for interaction on the part of the driver.

In addition to this main difference between an automatic transmission and a manual shift transmission, the organization of the gears is completely different. A manual shift transmission uses different gears to provide different levels of power; each set of gears is engaged when the gearshift is shifted. An automatic shift transmission uses a planetary model gear configuration. In a planetary model gear configuration, the same group of gears is used for each level of power, but they are placed in different combinations to achieve the desired result.

The A4LD transmission is an automatic transmission produced by Ford. This transmission uses the C-3 automatic transmission configuration but places an additional overdrive unit in front to achieve the four-speed configuration.