What kind of gear oil does a Subaru Forester take?

The correct oil depends on your Forester’s transmission and year: CVT-equipped models use Subaru CVT Fluid; manual transmissions typically require 75W-90 GL-4 gear oil; automatic transmissions use the manufacturer-specified ATF for your year; and the differentials have their own gear oil requirements. Always check your owner’s manual or a Subaru dealer for the exact specification and capacity.

CVT-equipped Foresters

The Forester’s Lineartronic CVT requires a dedicated CVT fluid rather than conventional engine oil or ATF. Subarus with a CVT use a specific CVT Fluid formulated to suit the belt/chain drive and the transmission’s hydraulic system.

• Subaru CVT Fluid (CVTF) that meets Subaru specifications for your model year and transmission.

In practice, using the factory-recommended CVTF is advised, and using non-CVTF fluids can affect shift quality and longevity. Always confirm the exact CVTF specification for your year with Subaru or your owner's manual.

Manual transmissions (5MT/6MT) in older Foresters

Manual transmissions in some older Forester models require a conventional gear oil that preserves synchros and gears. The typical recommendation is a GL-4 rating with a 75W-90 viscosity.

• 75W-90 GL-4 gear oil (or an equivalent GL-4 specification) for the manual transmission.

Note that some newer manuals and certain model years may differ. If your vehicle uses a different specification, refer to the manual or Subaru service guidance for the precise requirement.

Automatic transmissions

Foresters with traditional automatic transmissions use automatic transmission fluid (ATF). The exact specification can vary by model year, so it’s important to use the ATF recommended in your owner's manual, which may reference Dexron II/III compatibility or, in newer models, Dexron VI or Subaru’s own ATF formulation.

• ATF as specified by Subaru for your model year (often Dexron II/III compatible, with newer units using Dexron VI or Subaru ATF per the manual).

Using the wrong ATF can affect shift quality, temperature control, and transmission life, so verify the correct ATF type and change interval for your Forester’s year and transmission code.

Differentials and transfer case

Beyond the transmission, the all-wheel-drive system in a Forester has separate gear oil requirements for the front differential, rear differential, and, where applicable, the transfer case or center differential. These lubricants are not interchangeable with engine oil or transmission fluid.

• Front differential: 80W-90 GL-5 (check for any limited-slip additive requirements if applicable).


• Rear differential: 80W-90 GL-5 (same note about additives and LSD as needed).


• Transfer case/center differential (if equipped): gear oil per the owner’s manual; Subaru-specific formulations or GL-4/GL-5 ratings may be specified depending on year.

Because AWD differential and transfer case lubrication varies by model year and market, always consult the owner’s manual or a Subaru service specialist to confirm the exact oil type and capacity for your vehicle.

Summary

In short, Forester gear oil requirements differ by transmission type: CVT uses CVTF; manual transmissions typically require 75W-90 GL-4 gear oil; automatics require the factory-recommended ATF; and differentials use GL-5 80W-90 (with LSD considerations as indicated by your model). For any given year, the definitive source is your owner’s manual or a Subaru service professional, which will provide the exact specification, capacity, and change interval for your vehicle.

Notes for readers

If you’re planning a oil change or fluid service, gather the exact model year, transmission code, and any drivetrain options (like LSD) to ensure you purchase the correct lubricant. When in doubt, opting for Subaru’s factory fluids and following the official service schedule is the safest route to long-term reliability.

What type of oil is recommended for a Subaru Forester?

Recommended oil: 0W‑20 full synthetic. Subaru quick guides specify 0W‑20 meeting ILSAC GF‑5 / API SN (Resource Conserving) with normal change intervals at 6,000 miles under normal conditions.

What kind of fluid does a Subaru rear differential take?

Most Subaru models require 75W-90 GL-5 synthetic gear oil for the rear differential, but it's essential to confirm the exact specification for your vehicle. Valvoline, Subaru's own brand, and other high-quality brands like Red Line offer suitable products. Always check your owner's manual for the most accurate information and be sure to replace the crush washers on the drain and fill plugs when servicing. 
Recommended fluid specifications

• Weight: 75W-90
• API Rating: GL-5
• Type: Full synthetic is recommended for most applications 

How to check for the correct fluid

• Owner's Manual: The most reliable source for the correct fluid type and capacity is your Subaru's owner's manual. 
• Online Resources: Check forums like Reddit or sites like Advance Auto Parts by entering your car's make, model, and year.
• Dealer or Mechanic: A Subaru dealership or a trusted mechanic can confirm the exact specification for your vehicle. 

Important considerations

• Limited-Slip Differential (LSD): If your Subaru has a limited-slip differential, ensure the fluid is compatible with LSDs. Some fluids, like Red Line 75W-90 NS, are specifically made for manual transmissions and don't have the additives needed for a limited-slip rear differential. 
• Crush Washers: Always replace the crush washers on both the drain and fill plugs to ensure a proper seal. 
• Torque Specifications: Tighten the plugs to the manufacturer's specified torque. For some Subaru models, this is around 49 Nm or 37 foot-pounds. 

How to check Subaru gearbox oil?

Checking Your Transmission Fluid

1. Turn your engine on for a few minutes before proceeding.
2. Find the transmission fluid dipstick.
3. Remove the dipstick and touch the fluid, moving it around between your thumb and forefinger.
4. Use a rag to wipe off the dipstick.
5. Use a funnel to bring the fluid level up to the right spot.

Is gear oil the same as transmission oil?

No, gear oil and transmission oil are not the same; they are distinct fluids designed for different lubrication needs. Gear oil is typically a thicker, high-viscosity lubricant for manual transmissions and differentials, while "transmission oil" (or automatic transmission fluid, ATF) is thinner and formulated with additives for the hydraulic functions, cooling, and clutch engagement in automatic transmissions. Using the wrong fluid can lead to serious damage. 
Gear oil

• Used in: Manual transmissions and differentials.
• Key characteristics: Thicker, more viscous, and designed to withstand high pressure to protect gears under stress.
• Composition: Contains additives for high pressure protection. 

Transmission oil (ATF)

• Used in: Automatic transmissions. 
• Key characteristics: Thinner to allow for quick and efficient shifting and to facilitate hydraulic functions. 
• Composition: Contains special additives for cooling, cleaning, preventing foam, and working with clutch packs. 

Why they are different

• Viscosity: Gear oil is much thicker than ATF, which is thinner to work in a hydraulic system. 
• Function: ATF is a hydraulic fluid that also lubricates, while gear oil is a lubricant primarily designed for high-pressure gear protection. 
• Additives: The specific additives in each fluid are critical for its function. Using gear oil in an automatic can block narrow passages and cause overheating, while ATF may not have the high-pressure protection needed for a manual gearbox or differential.