Can I Use Engine Oil in My Gearbox? The Facts

Engine oil is a liquid lubricant for your car’s engine that coats all moving parts, eliminates built-up heat, and keeps everything hygienic.

While gear oil on the other hand is a liquid lubricant for your transmission, manual gearbox, transfer cases and differentials in your car or truck. It has high viscosity and contains organosulfur compounds to protect these gear systems from wear.

What is Gearbox Oil?

Gear oil is a lubricant used in transmissions, manual gearboxes, differentials, transaxles and transfer cases to keep these important internal parts running smoothly. Additionally, gear oil protects critical internal parts within these gear systems from wear and heat damage.

It’s essential to use the correct type and grade of gear oil for your vehicle. The reason for this is because inappropriate lubricant can lead to poor performance or even damage to your car’s gear system.

The American Petroleum Institute classifies gear oils according to their overall performance, using GL ratings. GL-4 and GL-5 oils are the most common, though heavier duty or high performance vehicles may require a higher GL-5 rating.

Check: Can You Mix Gear Oil With Engine Oil 

Difference Between Engine Oil and Gearbox Oil?

Can I Use Engine Oil in My Gearbox

Contrary to what they may appear like, engine oil and gear oil have distinct purposes in the vehicle industry. Thus, it is important to always use the correct lubricant for each application.

High-quality gear oil should lubricate, cool and protect geared systems while carrying away damaging wear debris away from contact zones and muffle the noise of gear operation. Furthermore, it must resist oxidation, thermal degradation, rust and copper corrosion.

Can I Use Engine Oil in My Gearbox?

Your car depends on a number of lubricants to stay running optimally. Whether it’s gear oil or motor oil, regular changes are essential for extending the lifespan of your vehicle and guaranteeing its smooth performance.

Always adhere to the manufacturer’s recommendations when changing your oil. Doing so can help protect your engine or transmission from any unnecessary damage.

Gearboxes in cars require a specially formulated lubricant to optimize performance of the transmission system. Therefore, putting engine oil into your gearbox could significantly impact its operation and affect vehicle performance.

How to Know When the Gearbox Oil Needs Changed?

No matter whether your car is manual or automatic, it’s important to check the gearbox oil level regularly. Low levels can cause your transmission to shift improperly or not at all, leading to costly repairs and unnecessary expenses.

Your owner’s manual should provide guidance on when to change your gearbox oil. Generally, it should be drained and refilled every 30,000 miles (50,000 km).


Engine oils provide protection for engines from heat, wear and damage. While Gear oils on the other hand lubricate transmissions, differentials and transfer cases in cars and trucks.

We think it would be best if you follow your vehicle’s manufacturer recommendation when it comes to choosing oils for your gearbox just to be on the safe side at all times.