The Difference Between Engine Oil, Transmission Oil, and Hydraulic Oil

Oil isn’t one-size-fits-all — each type serves a unique role in keeping your vehicle or machinery operating efficiently. Understanding the differences can help you prevent mechanical failures and choose the right lubricant for every system.

Engine Oil

Designed for combustion engines, engine oil reduces friction, prevents corrosion, and cleans internal parts. It operates under extreme heat and pressure, requiring additives to maintain performance over time.

Transmission Oil

Also known as transmission fluid, this oil lubricates the gears and bearings in your vehicle’s transmission. Automatic transmissions require fluids with specific frictional properties to enable smooth shifting and torque conversion.
Transmission oils are often dyed red and formulated to handle hydraulic pressure as well as mechanical stress.

Hydraulic Oil

Used in machinery like excavators, lifts, and brakes, hydraulic oil transmits power through pressurized systems. It must resist foaming, oxidation, and water contamination to ensure efficient operation.

Choosing the Right Oil

Always match the oil to the manufacturer’s specifications. Using the wrong type can lead to poor performance or permanent damage. PD Oils supplies all three — with specialized formulas for both automotive and industrial applications, ensuring every machine runs at its best.