🔧 Legacy - CVT Transmission Fluid Drain & Refill

This is a drain-and-refill service for the CVT (not a power flush). You’ll drain the old CVT fluid, refill with the correct Subaru CVT fluid, then set the fluid level using the level/overflow plug at a specific fluid temperature.

Difficulty Level: Intermediate | Estimated Time: 1.5-3 hours

Assumption: Your Legacy uses the TR580 CVT and Subaru CVTF-II fluid.

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⚠️ Safety & Precautions

• ⚠️ Work on a level surface; the CVT level check is inaccurate if the car isn’t level.
• ⚠️ CVT fluid can be hot and can burn you—wear gloves and safety glasses.
• ⚠️ Use jack stands; never rely on a floor jack alone.
• ⚠️ Keep the engine OFF while draining; the level check is done with the engine running (later).
• ⚠️ Use only Subaru-spec CVT fluid; the wrong fluid can damage the CVT.
• 🔌 Battery disconnect is not required for this service.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Safety glasses
• Nitrile gloves
• Drain pan (10-quart minimum)
• Metric socket set (8mm-19mm)
• 3/8" drive ratchet
• Torque wrench (10-100 ft-lbs range)
• Trim clip remover tool
• Flathead screwdriver
• 6mm hex bit socket
• Fluid transfer pump (specialty)
• OBD2 scan tool that reads CVT/ATF temperature (specialty)
• Shop rags
• Funnel with hose
• Measuring container (quart/liter marked)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Subaru CVT fluid (CVTF-II) - Qty: 6 quarts
• CVT drain plug crush washer - Qty: 1
• CVT level/overflow plug crush washer - Qty: 1

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📋 Before You Begin

• Park on a flat, level surface and chock the rear wheels.
• Raise the front and rear and support with jack stands so the car sits level in the air.
• Gather your scan tool. You’ll use it to monitor CVT fluid temperature (this is the temperature of the fluid inside the transmission).
• Lay out a measuring container so you can measure how much fluid comes out (this helps you get close on the refill).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the undertray/splash shield

• Use a trim clip remover tool and flathead screwdriver to remove the plastic clips.
• Use a 10mm socket with a 3/8" drive ratchet to remove any bolts holding the undertray.
• Set the panel and clips aside in a small pile so you don’t lose them.

Step 2: Locate the CVT drain plug and level/overflow plug

• Place your drain pan (10-quart minimum) under the CVT.
• Use a flashlight (from your phone is fine) to identify the CVT drain plug at the bottom of the transmission.
• Identify the level/overflow plug on the transmission case/pan area (this plug is used to set the final fluid level).

Step 3: Crack the level/overflow plug loose first

• Use a 6mm hex bit socket with a 3/8" drive ratchet to carefully loosen the level/overflow plug.
• If it won’t loosen, stop and do not drain yet. You must be able to re-check level.

Step 4: Drain the old CVT fluid

• Use the correct metric socket (commonly 14mm socket) with a 3/8" drive ratchet to remove the CVT drain plug.
• Let the fluid drain fully into the drain pan (this may take 10-20 minutes).
• Pour the drained fluid into your measuring container so you know how much came out.
• Replace the drain plug crush washer with the new CVT drain plug crush washer.

Step 5: Reinstall and torque the CVT drain plug

• Thread the drain plug in by hand first (to avoid cross-threading).
• Use a torque wrench (10-100 ft-lbs range) to tighten the drain plug: Torque to 44 Nm (32 ft-lbs).
• Wipe the area clean with shop rags so you can spot leaks later.

Step 6: Refill CVT fluid (initial fill)

• Locate the CVT fill port (top-side fill plug/port on the transmission).
• Use a fluid transfer pump (specialty) and/or funnel with hose to add new Subaru CVT fluid (CVTF-II).
• Add roughly the same amount you measured coming out (usually around 4-6 quarts on a drain-and-refill).
• Reinstall the fill plug snugly using the appropriate metric socket (do not over-tighten yet if access is awkward).

Step 7: Circulate fluid and bring CVT fluid to level-check temperature

• Plug in your OBD2 scan tool that reads CVT/ATF temperature (specialty).
• Start the engine and let it idle.
• With your foot on the brake, move the shifter slowly through P-R-N-D, pausing 3 seconds in each position, then return to P.
• Monitor CVT fluid temperature on the scan tool and warm it to 35-45°C (95-113°F) for the level check.

Step 8: Set the final CVT fluid level at the overflow/level plug

• With the engine idling and the car level on stands, place the drain pan under the level/overflow plug.
• Use the 6mm hex bit socket with a 3/8" drive ratchet to remove the level/overflow plug.
• Correct level behavior:
• If fluid streams out heavily, let it drain until it becomes a light trickle.
• If nothing comes out, add CVT fluid through the fill port using the fluid transfer pump (specialty) until fluid just begins to trickle from the level hole.
• Once it’s a light trickle/drip at the correct temperature, install a new CVT level/overflow plug crush washer and reinstall the plug.
• Use a torque wrench to tighten the level/overflow plug: Torque to 20 Nm (15 ft-lbs).

Step 9: Reinstall undertray

• Reinstall the undertray using a 10mm socket and 3/8" drive ratchet.
• Reinstall clips with the trim clip remover tool (push-pin style clips press in by hand after the center pin is raised).

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✅ After Repair

• With the car still level, let it idle for 1-2 minutes and inspect for leaks at the drain and level plugs using shop rags.
• Road test 10-15 minutes. Verify smooth takeoff and no flare or shudder.
• Recheck for leaks after the road test.
• If you have a scan tool, check for any stored transmission codes and make sure none return.
• Dispose of used fluid at a recycling center.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $80-$160 (parts only)

You Save: $170-$290 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.