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heticor · 10-01-2021, 01:52 PM

I have been reading a lot about the recommended Oil form the front and rear differential.

According to Real Oem there is one for the front and one for the rear.

the front diff oil part number is 83222413511, Hypoid axle oil G2, SAE 75W-85 GL 5.
The rear diff oil part number is 83222295532 Hypoid axle oil G1, SAE 75W-85 GL4.

Many people uses the same oil from the front and rear, however they are different products. here a section of article that I found.

"When you are choosing a transmission or gear oil you might be wondering what GL-4 and GL-5 mean and what the differences are between these two classifications. Choosing the right classification is extremely important since they both have different properties and wrongful use could lead to serious damage to your vehicle.

There are four different classifications for transmission/gear oil. These different classifications define a certain level of performance in driven axles and manual gearboxes. They are mainly important for the transport sector in North America, Africa and Asia. The active classifications are:

GL-1
GL-4
GL-5
MT-1
The higher the Extreme Pressure (EP), the higher the GL category is. It is important to know that the SAE Motor Oil Viscosity Chart (J300) is different from the SAE Gear Oil Chart (J306). The viscosity has no relation with the API Gear Oil Classification and should be chosen based on the recommendations from the manufacturer based on the temperatures where you will drive.

The main difference between GL-4 and GL-5 gear oils is the amount of EP additives. Sulphur/Phosphorus containing products are used as EP-additive. This additive has the purpose to prevent the occurrence of micro-welds on the gear flanks at the local high temperatures which prevail in EP circumstances (temperatures well in excess of 800℃!) GL-5 has roughly twice the amount of EP additives compared to GL-4, which is why it is often used in high-pressure circumstances such as in a front axle and rear axle differential.

Sulphur/Phosphorus additives however have an unfavourable property: they can react aggressively towards bronze and copper. This can be disastrous for the synchromesh rings of a gearbox. Therefore it is not recommended to use GL-5 in a gearbox unless the manufacturer allows this.

To conclude:

GL-4 is suitable for hypoid gear service when they are under severe service but are without shock loading.
GL-5 is suitable for hypoid gear service under severe service and shock loads and not for use in a gearbox."

I am looking for the most economical but good quality oil for the differentials, what brand do you guys recommend?

10-01-2021, 01:52 PM	#1
heticor Private 21 Rep 54 Posts Drives: BMW X3 Join Date: Jul 2021 Location: NB Canada iTrader: (0)	Differential front and Rear Oil spec. I have been reading a lot about the recommended Oil form the front and rear differential. According to Real Oem there is one for the front and one for the rear. the front diff oil part number is 83222413511, Hypoid axle oil G2, SAE 75W-85 GL 5. The rear diff oil part number is 83222295532 Hypoid axle oil G1, SAE 75W-85 GL4. Many people uses the same oil from the front and rear, however they are different products. here a section of article that I found. "When you are choosing a transmission or gear oil you might be wondering what GL-4 and GL-5 mean and what the differences are between these two classifications. Choosing the right classification is extremely important since they both have different properties and wrongful use could lead to serious damage to your vehicle. There are four different classifications for transmission/gear oil. These different classifications define a certain level of performance in driven axles and manual gearboxes. They are mainly important for the transport sector in North America, Africa and Asia. The active classifications are: GL-1 GL-4 GL-5 MT-1 The higher the Extreme Pressure (EP), the higher the GL category is. It is important to know that the SAE Motor Oil Viscosity Chart (J300) is different from the SAE Gear Oil Chart (J306). The viscosity has no relation with the API Gear Oil Classification and should be chosen based on the recommendations from the manufacturer based on the temperatures where you will drive. The main difference between GL-4 and GL-5 gear oils is the amount of EP additives. Sulphur/Phosphorus containing products are used as EP-additive. This additive has the purpose to prevent the occurrence of micro-welds on the gear flanks at the local high temperatures which prevail in EP circumstances (temperatures well in excess of 800℃!) GL-5 has roughly twice the amount of EP additives compared to GL-4, which is why it is often used in high-pressure circumstances such as in a front axle and rear axle differential. Sulphur/Phosphorus additives however have an unfavourable property: they can react aggressively towards bronze and copper. This can be disastrous for the synchromesh rings of a gearbox. Therefore it is not recommended to use GL-5 in a gearbox unless the manufacturer allows this. To conclude: GL-4 is suitable for hypoid gear service when they are under severe service but are without shock loading. GL-5 is suitable for hypoid gear service under severe service and shock loads and not for use in a gearbox." I am looking for the most economical but good quality oil for the differentials, what brand do you guys recommend?
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