Why gearbox oil should have high viscosity?

The high viscosity index also makes synthetic products suitable for a wider range of ambient temperatures, eliminating the need for seasonal oil changes. Some synthetics may also offer greater lubricity which reduces friction in sliding contacts.

Is gear oil more viscous than engine oil?

It should be noticed that there is no relationship between the SAE engine oil and gear oil classifications. A gear lubricant and an engine oil having the same viscosity will have widely different SAE grade designation as defined in the two classifications.

What viscosity is gear oil?

The viscosity of synthetic oils according to the ISO grading system is between 32 to 6800. Synthetic gear oils are used for gears operating under extreme conditions: very low or very high temperatures, high pressures.

Why is gearbox oil thick?

The high viscosity ensures that the entire gear train is lubricated thoroughly and, most importantly, that the gears are well cushioned from shock damage when they come together. The working of a manual gearbox creates a lot of friction and therefore a lot of heat.

What causes oil viscosity to decrease?

Oils operating at extreme high temperatures can begin to crack thermally. The high temperatures can sheer/crack the oil molecules into smaller molecules, which causes a decrease in viscosity.

What is the meaning of 80w90?

80W-90. The numbers “80W-90” refer to the viscosity grades of the oil. Since it has two numbers, this oil has two viscosity grades. The ‘W’ means winter. The number “80” — in this case — signifies that the oil is designed to work well in lower temperatures.

Is gear oil heavier than water?

Gear Oil API Gravity If the API gravity is greater than 10, then the oil is lighter than water and will float on top of it; if the API gravity is less than 10, then the oil is heavier than water and will sink. The API for a gear oil is determined according to ASTM D287.

What is the difference between gear oil and transmission oil?

The simplest answer to the difference between transmission fluid and gear oil is in the purpose for which they are designed. Transmission fluid is engineered to work with automatic transmissions, whereas gear oil is typically intended to work with manual-type gear boxes.

Is higher viscosity oil thicker or thinner?

Let’s Get You an Oil Change You can find the viscosity rating directly on the oil’s bottle. All motor oils have viscosity ratings given by the the Society for Automotive Engineers, with the most common viscosity grade being 5W-30. The higher the number, the thicker the oil. The lower the number, the thinner the oil.

What is gl5 gear lube?

DESCRIPTION. GL-5 Heavy Duty Gear Oil is an extreme pressure, multi-purpose, automotive gear lubricant. Excellent performance for differentials operating under high speed, low torque; and low speed, high torque conditions. It meets SAE, military and commercial specs.

What’s thicker 75w90 or 75W140?

The main asymmetry between 75w90 and 75w140 is that at operating temperature, the 75W140 will be significantly thicker than the 75w90. However, at room temperature, they both will be of similar density.