How Does Transmission Fluid Work?

September 17, 2021 1:22 pm


When the engine is running, a shaft fluid travels up under the engine’s crankshaft and down into the transmission tunnel under high pressure formed by the oil pump. Once the fluid has been pressurised, it runs through the transmission so it can operate the clutch.  The transmission fluid is compressed and escapes through a larger tube that goes directly into the engine’s combustion chamber. This tube is often referred to as an ‘intake’ or ‘exhaust’ tube – it is vital that there be no leaks, otherwise the engine will not run.

Image credit

The transmission fluid is pumped back up and out of the engine via the intake manifold. The intake manifold is usually located behind the engine or right below it. Up until fairly recently, fuel injection was done with a pump which put liquid diesel or gasoline (and sometimes other fluids) in the engine’s intake manifold. These days, fuel injection is performed by electric pumps which are very similar to vehicle tyre air pumps. The fluid flows past a hydraulic arm that is able to actively manipulate the clutch – so that there is maximum pressure on the gas or liquid, and minimum pressure on the clutch. For more details on Fluid Power, visit

Image credit

In order to answer this question, you must be able to at least partially understand the science behind the operation of a ‘transmission’. First of all, the way that a transmission operates is pretty straight forward – the rotation of an axle moves a drive assembly down into the transmission. This assembly, also known as a ‘clutch’, then causes a chain reaction that leads to the movement of the axle and the transmission of the fluid.