How Much Rear Axle Gear Oil Should Be Added?
2 Answers
Rear axle gear oil standard is 150 milliliters, which is sufficient. Working conditions of rear axle gear oil: The contact area between gears is very small, basically line contact, and during movement, there is both rolling friction and sliding friction. Thus, the working conditions of gear oil are significantly different from other lubricants. Due to the small contact area between gears, the pressure they endure is very high. The tooth surface pressure of some heavy machinery reducer gears can reach 400–1000 MPa. The operating conditions of hypoid gears in automotive transmission systems are even more demanding, with heavier loads, and the pressure at the contact points can be as high as 1000–4000 MPa. Under such high pressure, the lubricating oil is easily squeezed out from between the teeth, which can lead to tooth surface scuffing and wear. Therefore, gear oil must have the performance to maintain the tooth surfaces in a state of boundary lubrication and elastohydrodynamic lubrication under high loads. Functions of rear axle gear oil: Lubricate the transmission system, reduce wear on gears and moving parts, ensure normal operation of the transmission system, and extend service life. Reduce friction and transmission losses in gear transmission, improving mechanical efficiency. Cool transmission components. Gear transmission generates a large amount of heat due to tooth surface contact friction. If not dissipated in time, it can cause localized high temperatures on the tooth surfaces, and in severe cases, lead to burning and adhesion. During the circulating lubrication process, gear oil continuously carries away heat, dissipating it through the air and the transmission housing, ensuring normal operation of the transmission components. Prevent corrosion and rust. Reduce tooth surface impact and transmission noise.
I just changed the rear axle fluid for my old pickup truck last month, and the required amount really depends on the specific model. For sedans, it's generally between 1.2 to 1.5 liters, but for my pickup, it takes about 1.8 liters. The most reliable method is to check the service manual. If you don't have the manual, crawl under the vehicle to look at the rear axle housing—it usually has the capacity markings cast on it. If you're doing it yourself, pay close attention: the fluid should be filled until it overflows from the inspection hole. Too much fluid will cause leaks, and too little will burn out the bearings. By the way, rear axle fluid usually needs to be changed every 40,000 kilometers or two years, especially for vehicles that frequently drive on rough roads—they should be changed even earlier.
