Gear oil 75W90, 85W90, 80W90 or 75W140 - which one to choose?

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

Spending an extraordinary amount for 75W90 gear oil, motorists are usually sure that this is an acceptable quality lubricant. You can try to go even further and choose a fluid that would suit a particular car model and was not overpriced for the money.

Transmission classes

Lubricants of the Gl group are hypoid. That is, they lubricate the rear axles and individual gearboxes of such domestic car brands as Zhiguli, Niva, Volga. For trucks, of course, it will also work, but it will cost too much.

The most common gear oil is 75W90 viscosity grade. Exceptions included Castrol brand oils. Their line includes lubricants 85W90 and more liquid 80W90. In addition, transmission oil 75W140 stood next to GL 5 75W90. This last viscosity option is not very suitable for Russian cars. It is usually poured into the rear and all-wheel drive versions, as well as in models with a lockable differential. They are most likelythey will serve perfectly on the Patrol or Land Cruiser, but for domestic ones they will be too thick. It makes no sense to fill them in during normal operation. But if the rear axles “sang”, then such a lubricant may suit them just right.

But if an inexpensive mineral water does its job well, why spend extra money on synthetics?

Gear oils of different viscosities

Among motor oils, a completely artificial synthetic base has long gained the greatest popularity. They are followed by transmission oil 75W90, 85W90, 75W140. Most synthetic-based lubricants can be used all year round. Even at very low temperatures, they will give good functional results. For example, if you compare 85W90 mineral water at negative twelve degrees with 75W140 synthetics in frost at forty degrees, then the viscosity result will be almost indistinguishable. And if they are placed in the same temperature regime at -20 degrees, then the result will be 30-50 times different. This is a very serious undertaking. It turns out that in one case the engine will barely start, and in the other - almost like in the warm season.

Lubricant testing

Dignity will be revealed even more if you try them in operation under extreme conditions. Under heavy loads, lubricating fluids become more fluid. Therefore, appropriate tests were carried out. Of course, it was expected that those with higher quality,here they will behave better and show the most stable results. And so it happened.

Clearer the result will be visible in numbers. Welding load on a conventional 4-ball friction machine reveals the ability to hold a critical load. According to it, the oils are divided into groups. So, GL 3 has a minimum value of 2760N, gear oil 75W90 - GL 4 - 3000N, and GL 5 - 3280N.

Test results

And the test results were as follows. The cheapest 85W90 viscosity oils had from 2607 to 4635N. Their average is 3827N. It would seem that it exceeds even GL 5. But let's look further. AvtoVAZ needs a transmission with an indicator above 3483N, and AZLK - 3924N. To meet such requirements, the result is no longer seen as excellent.

The other test oil had a viscosity of 80W90. Its average value gave the number 4122N, which is already much better. Gear oil 75W90 showed an even better result. Here the values ranged from 3685 to 5204N, and the average was 4508N, which certainly pleased.

The best results were of course given to the 75W140 viscosity. However, such a transmission is hardly necessary for everyone.

So what oil to use?

Summarizing the above, we can conclude that if the operation of the vehicle is supposed to be at a temperature not lower than -12 degrees, then it is quite possible to get by with oil with a viscosity class of 85W90. This is the most inexpensive option, and domestic productionvery cheap.

If the temperature in the area drops to 26 degrees below zero, then you need to purchase 80W90 oil. With it, with such a mark, the car will feel more confident.

Well, 75W90 gear oil, reviews of which can be found on the net very often, and even more so of the 75W140 viscosity class, is already left for fans of extreme driving. Of course, and the price will be higher.

Calculating the required amount (for example, on the Zhiguli - the rear axle takes about three liters) and comparing it with the mileage (on the same brand, a replacement is required every 60,000 km), each motorist can calculate how much money it will cost him this or that oil, and based on this data, make a choice.

If we talk about specific brands of transmission lubricating fluids, we can note several foreign oils that have shown good results:

• Wellrun set a record for welding load.
• Liqui Moli is the all-time cold hardiness record.
• Castrol 75W140 is the best result in terms of resistance to overheating.
• Spectrol Synax (domestic brand) met all standards, but fell short of high requirements.