What is Acura rear differential fluid?
Acura rear differential fluid is the gear oil used to lubricate the rear differential in Acura vehicles, particularly those with all-wheel drive. It is not the same as engine oil or automatic transmission fluid, and it typically requires a synthetic gear oil conforming to specific specifications such as API GL-5 with a viscosity around SAE 75W-90. Always check your owner’s manual or a dealer for the exact spec for your model year.
Understanding the role of this fluid helps explain why maintenance matters: the rear differential transmits power to the rear wheels, and its gears operate under high pressure and heat. The right oil reduces wear, carries heat away, protects gear surfaces, and keeps the differential functioning smoothly, especially in models with limited-slip or performance torque-vectoring diffs. Specifications can vary by model and year, so model-specific guidance is essential.
Understanding Acura rear differential fluid
The rear differential is a sealed housing that contains gears, bearings, and sometimes a limited-slip mechanism. The lubricant inside forms a film that minimizes metal-to-metal contact, lowers operating temperatures, and prevents corrosion. Because these gears operate under high load and pressure, the fluid needs to be a high-performance gear oil with anti-wear and extreme-pressure additives. Acura typically recommends a synthetic gear oil that meets API GL-5 specifications, with a viscosity of SAE 75W-90 for most modern vehicles. Some models with special diffs or climate conditions may require different viscosities or additives, which is why the owner’s manual is the definitive source.
Typical specifications for Acura rear differentials
Below are common attributes you’ll encounter for Acura rear-differential lubrication. This list summarizes typical guidance; variations exist by model and production year.
Before listing the typical specs, it helps to know what to expect when shopping for or replacing the oil. The following points cover the general expectations across many Acura AWD/RWD applications.
- Fluid type and performance: synthetic gear oil that meets API GL-5 is standard for most Acura rear differentials.
- Viscosity: SAE 75W-90 is the most commonly specified grade for modern Acura models, offering good cold-weather flow and high-load protection.
- Special cases: some models with limited-slip diffs or torque-vectoring setups may require a different viscosity (such as 75W-140) or the addition of a friction-modifier additive; always verify with the manual or dealer guidance.
- Compatibility: use gear oil designed for axles/differentials (not engine oil or automatic transmission fluid). Do not mix different oil types or brands beyond what the manual allows.
- Maintenance interval: replacement or inspection is typically recommended at intervals around 30,000–60,000 miles under normal driving, with more frequent service in severe conditions; consult the owner’s manual for model-specific timing.
In practice, the exact specification and interval depend on the specific Acura model and year. Rely on the owner's manual or a certified Acura technician to confirm the correct oil grade, quantity, and service schedule for your vehicle.
Maintenance and service guidelines
Keeping the rear differential properly filled with the correct fluid is essential for long-term drivetrain health. Signs that the fluid may need attention include unusual whining, grinding noises, or heat emanating from the rear area, as well as visible leaks around the differential. If you notice any of these symptoms, consult a qualified technician to inspect and service the differential with the proper gear oil and any required additives.
Before performing any service, verify the exact specification for your model year and transmission/differtype. If you’re not comfortable handling a differential fluid change, a dealership or ASE-certified shop can perform the service with the correct lubricant and procedures.
How to check or replace rear differential fluid (general guidance)
Understanding the basic approach can help you discuss service with a technician or prepare for a DIY task. The steps below describe a typical process, but always follow your vehicle’s specific instructions in the owner's manual.
- Confirm the correct oil grade and capacity for your model year from the manual or dealer.
- Warm up the vehicle slightly and park on level ground; safely lift and support the car if you will access the differential drain and fill plugs.
- Place a drain pan under the differential and remove the drain plug to allow old fluid to drain completely.
- Remove the fill plug and check that the differential housing can take new oil to the proper level; if the system uses a level check, fill until oil begins to seep from the fill hole (or until the commanded level is reached per the manual).
- Install a new gasket or washer on the drain and fill plugs as required, torque to factory specifications, and clean up any spills.
- Dispose of the old gear oil responsibly at a recycling facility or dealership that accepts used fluids.
After completing the service, drive briefly to circulate the new oil, then recheck for leaks and ensure the vehicle operates normally. If you’re unsure about the process or the correct oil, seek professional service to avoid overfilling or underfilling, which can harm the differential.
Summary
Acura rear differential fluid is the specialized gear oil used to lubricate the rear differential in Acura vehicles, most commonly a synthetic oil meeting API GL-5 with a typical viscosity of SAE 75W-90. Specifications can vary by model and year, especially for units with limited-slip or performance diffs, so always verify the exact requirements in the owner's manual. Regular checks and timely changes help protect the differential, reduce wear, and maintain drivetrain reliability. When in doubt, consult an Acura dealer or a qualified technician for guidance tailored to your vehicle.
