What kind of oil goes in a rear diff?
The rear differential is a critical component of your vehicle's drivetrain, responsible for transferring power from the engine to the wheels while allowing them to rotate at different speeds. Choosing the right oil for your rear differential is essential for maintaining its performance and longevity. In this article, we’ll explore the types of oil commonly used in rear differentials and how to determine the best option for your vehicle.
Understanding Rear Differential Oil
Rear differential oil, also known as gear oil, is specifically designed to lubricate the gears and bearings within the differential. This oil must withstand extreme pressure and high temperatures, ensuring smooth operation and preventing wear and tear. Using the wrong type of oil can lead to premature wear, overheating, and even failure of the differential.
Types of Rear Differential Oil
There are several types of oil that may be suitable for your rear differential, depending on your vehicle's make, model, and usage. Here are the most common options:
- Conventional Gear Oil: This is the standard oil used in many vehicles. It provides adequate lubrication for everyday driving conditions and is often specified in older vehicles.
- Synthetic Gear Oil: Synthetic oils are engineered to offer superior performance, especially in extreme temperatures or under heavy loads. They are ideal for modern vehicles or those used for towing and off-roading.
- Limited-Slip Differential Oil: If your vehicle has a limited-slip differential, you’ll need oil that includes friction modifiers. These additives ensure proper operation of the limited-slip mechanism.
How to Choose the Right Oil for Your Rear Differential
To determine the correct oil for your rear differential, follow these steps:
- Check Your Owner’s Manual: The manufacturer’s recommendations are the best place to start. Your owner’s manual will specify the type and viscosity of oil required for your vehicle.
- Consider Your Driving Conditions: If you frequently tow heavy loads, drive in extreme temperatures, or go off-roading, synthetic gear oil may be a better choice for enhanced protection.
- Consult a Professional: If you’re unsure about the right oil for your vehicle, consult a trusted mechanic or auto service provider. At Kevin’s Autos, we’re always happy to help you make the best choice for your car.
When to Change Your Rear Differential Oil
Regular maintenance is key to keeping your rear differential in good condition. Most manufacturers recommend changing the differential oil every 30,000 to 60,000 miles, but this can vary based on your vehicle and driving habits. Signs that it may be time for a change include unusual noises from the rear of the vehicle, difficulty turning, or a burning smell.
Conclusion
Choosing the right oil for your rear differential is crucial for ensuring smooth operation and extending the life of this vital component. Whether you opt for conventional, synthetic, or limited-slip differential oil, always follow your manufacturer’s recommendations and consider your driving conditions. If you have any questions or need assistance, don’t hesitate to reach out to us at Kevin’s Autos. We’re here to keep your car running smoothly!
Frequently Asked Questions
Which lubricant would one expect to be used in a rear differential?
Normally it will be an Extreme Pressure (EP) Gear Oil, typically EP80. However, some rear diffs such as limited slip diffs (LSD's) require a special LSD oil which will be specified by the diff manufacturer if fitted as an 'add on' for special use or by the vehicle manufacturer if fitted as OE.
Which grade of oil is used in differential?
Separate differentials usually have higher pressure between metal parts than gearboxes and therefore need higher GL-rating. For example, most modern gearboxes require a GL-4 oil, and separate differentials (where fitted) require a GL-5 oil.
What fluid would most likely go in a rear differential?
Gear oil (e.g., SAE 75W-90, 75W-140, 80W-90, 80W-140, 85W-140) is the most common differential fluid. Some differentials use limited slip additives.
Which is thicker 75W90 or 75W140?
So, the difference between "75W90" and "75W140" is that at operating temperature, the 75W140 will be considerably thicker than the 75W90 but at room temperature they will be about the same viscosity.
Can I use 75W90 instead of 75W80?
If both 75W80 and 75W90 are approved for your car, you have the choice. Basically, the gear oils do not differ much from each other. 75W90 has a higher kinematic viscosity than 75W80.
What can you use instead of gear oil?
Typically, semi-fluid greases such as NLGI #000 or #00 are recommended for small gearboxes that frequently are run to fail. This strategy simplifies maintenance practices by reducing the chance of a leak and the need to top up components.
What is the difference between 80w90 and 75W90 gear oil?
When run under real-world line-haul conditions, the use of 75W-90 can improve the efficiency of a Class 8 axle by an average of 0.5% over an axle using 80W-90. Considering that axles themselves are 95% efficient, a gain of 0.5% is significant.
What fluid should never be used in a rear differential?
Never, under any circumstances, put engine oil in your differential. This will result in devastating damages to your engine. Engine oil is much different than gear oil, mostly it cannot withstand high pressure.
Is gear oil the same as rear differential fluid?
The differential fluid, also known as gear oil, is specifically formulated to lubricate and protect the gears and bearings within the differential housing. On the other hand, transmission fluid is responsible for lubricating and cooling the intricate components of your vehicle's transmission system.
What oil to use in rear differential?
75W90 GL-5 Gear Oil
The go-to gear oil for most differentials.
