What is gear oil?
Gear oil lubricates the manual gearboxes of machinery and vehicles, ensuring they operate smoothly and safely to provide a comfortable ride and flawless performance.
Without proper lubrication, gears will become damaged by friction, corrosion and the effects of extremely high and low temperatures. All these can reduce performance and component lifespans as well as increasing costs, but certain models require particular lubricants, so it’s important to get the correct gear oil for your vehicle or equipment.
What is transmission oil?
Transmission oil is similar to gear oil but used to lubricate the entire drivetrain – including the gearbox, prop shaft, clutch, differential and final drive shafts. The term transmission oil is also regularly used to describe lubricants specifically designed for automatic transmissions (known as ATF). Transmission components require lubrication so they can operate efficiently and aren’t damaged.
Can you use gear oil for power steering fluid?
It’s important that you don’t use gear oil as power steering fluid. The two lubricants have different formulations, and thus shouldn’t be used interchangeably, or you may harm the components and their performance. Some ATFs can be used as power steering fluid, but this will be clearly stated by the manufacturer, so never assume your transmission or gear oils can be used to lubricate power steering systems.
TotalEnergies has a wide range of premium gear and transmission oils on offer, formulated with the latest additives and formulations to ensure your gearbox or transmission operates perfectly. Scroll to the bottom of the page to view our extensive range, designed for cars, machinery, and both light and heavy commercial and industrial vehicles.
The differences between gear oil grades
When shopping for the right gearbox oil, it’s a good idea to understand gear oil grades. The most common are automotive SAE (Society of Automotive Engineers) and industrial ISO (International Organization for Standardization) grades.
Gear oil SAE grades are numbered 60 or above. Similar to monograde engine oil SAE grades, monograde gear oil grades use one number – oils for colder seasons using digits followed by a ‘W’ (SAE 75W), and oils for hotter seasons simply using a number (SAE 75). The higher this figure is, the greater the oil’s viscosity.
Multigrade SAE grades feature two numbers separated by a ‘W’ (such as 85W120), with the digits before the ‘W’ noting 0°C performance and the following number its 100°C performance – the higher these numbers are, the more viscous the oil is at those temperatures.
ISO grades rate industrial gear oils, using a single figure. The higher the digits, the greater the lubricant’s viscosity – the number mirrors the mid-point viscosity number in centistokes (cSt). For example, ISO 3 equals 3.2 cSt and ISO 220 equals 220 cSt.
Learn more about the difference between grade X and grade Y gear oils.
When and how to check and change your gear oil and filter
Gear oil keeps your gears and transmission performing efficiently, without the risk of damage, but it needs changing every so often. If your model doesn’t feature an oil life monitoring system with automatic alerts, knowing when to change gear oil (and its filter) can be difficult to work out, but there are broad guidelines:
- Manual gearboxes – a change every 30,000 to 50,000 mi (48,000 to 80,000 km).
- Automatic gearboxes – a change every 60,000 to 100,000 mi (96,000 to 160,000 km).
- It’s a good idea to change your gearbox oil filter alongside your oil.
- If you have a gearbox leak repaired, change your oil after the repair.
These ranges are large, so a good way to check your oil health is by assessing its colour. New oils are often bright red and semi-transparent, but grow darker, less transparent and smell burnt as they reach the end of service.
To check your gearbox oil:
- Locate the transmission dipstick. If your model doesn’t have one, you may need to raise your car then remove the transmission fill cap on the transmission assembly.
- Pull the dipstick out of its tube. If the car is raised, insert an implement into the system.
- Check the colour of the oil.
If the oil is brown, black or light pink, it will need replacing.
For full instructions on how and when to change gear oil, view our full-length guide.
TotalEnergies' range of gear and transmission oils
Compatible with all common car and commercial vehicle makes and models, TotalEnergies' selection of transmission and gear lubricants include:
Lubricant for automatic or semi-automatic transmissions and torque converters of passenger cars, light commercial vehicles and industrial vehicles.
Automatic transmission fluid formulated with premium base stocks and carefully selected additives to meet the challenging demands of automatic transmissions.
Extreme pressure mineral manual transmission fluid for highly loaded gears.
High-performance manual transmission lubricant for synchronised and non-synchronised axles and reduction gears.
Transmission fluid specially designed for the lubrication of manual gear boxes of passenger cars.