🔧 NX200t - Automatic Transmission Fluid Drain & Fill (WS)

This service replaces a portion of the old automatic transmission fluid by draining the pan and refilling with the correct fluid. Your NX200t uses a “sealed” style level-check system, so the fluid level must be set at a specific transmission-fluid temperature.

Difficulty Level: Advanced | Estimated Time: 2-3 hours

Assumption: U.S.-spec 6-speed automatic using Toyota/Lexus ATF WS and overflow level-check method.

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⚠️ Safety & Precautions

• ⚠️ Work on a level surface; support the NX200t on jack stands (never the jack alone).
• ⚠️ Transmission fluid can be very hot; wear gloves and safety glasses.
• ⚠️ Keep the vehicle level front-to-rear and side-to-side during level setting, or the fluid level will be wrong.
• ⚠️ Engine will run during the final level check; keep hands/clothes away from belts/fans.
• 🔋 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 (at least 10-quart)
• Socket set with ratchet (8mm, 10mm, 12mm sockets)
• Allen hex bit socket set (5mm, 6mm, 10mm)
• Trim clip removal tool
• Torque wrench (10-100 Nm range)
• Fluid transfer pump (hand pump) (specialty)
• OBD2 scan tool that reads transmission fluid temperature (specialty)
• Shop towels
• Brake cleaner spray

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid (Toyota/Lexus ATF WS) - Qty: 5 quarts
• Transmission drain plug crush washer/gasket - Qty: 1
• Transmission fill plug gasket - Qty: 1
• Transmission overflow/level plug gasket - Qty: 1
• Undercover fastener clips - Qty: 2

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📋 Before You Begin

• Park on a flat, level surface and set the parking brake.
• Chock the rear wheels with wheel chocks.
• Raise and support the NX200t so it sits level on jack stands.
• Get your OBD2 scan tool ready to view Transmission Fluid Temperature (often labeled “ATF Temp”). This is the key to setting the level.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the lower undercovers

• Use a trim clip removal tool to pop the plastic clips without breaking them.
• Use a 10mm socket (and 12mm socket if equipped) to remove the bolts holding the undercovers.
• Set all hardware aside in a tray so nothing gets lost.

Step 2: Locate the drain, fill, and overflow (level) plugs

• Place a drain pan under the transmission.
• Identify the fill plug (side of the transmission case) and the drain plug (bottom area).
• Identify the overflow/level plug (smaller internal plug/standpipe access, depending on version).
• Pro tip: Clean dirt off plug areas first.

Step 3: Loosen the fill plug first

• Use the correct Allen hex bit socket (commonly 10mm) with a ratchet to crack the fill plug loose.
• This prevents a bad day where you drain it first and then find the fill plug is stuck.

Step 4: Drain the old transmission fluid

• Position the drain pan under the drain plug.
• Use the correct Allen hex bit socket with a ratchet to remove the drain plug.
• Let it drain until it slows to a drip (typically 10-20 minutes).
• Clean the drain plug with shop towels and brake cleaner spray.

Step 5: Reinstall the drain plug with a new gasket

• Install a new drain plug crush washer/gasket.
• Thread the drain plug in by hand first to avoid cross-threading.
• Use a torque wrench to tighten: Torque to 49 Nm (36 ft-lbs).

Step 6: Pump in new ATF WS through the fill port

• Remove the fill plug fully using the Allen hex bit socket.
• Use a fluid transfer pump (a hand pump that pushes fluid uphill into the transmission) to pump in ATF WS.
• Add fluid until it begins to dribble out (or until you’ve added about what you drained, if you measured it).
• Reinstall the fill plug finger-tight for now (you’ll reopen it if needed during level set).

Step 7: Set the fluid level at the correct temperature (overflow method)

• Connect your OBD2 scan tool and monitor ATF Temp.
• Start the engine and hold the brake firmly.
• Slowly move the shifter through P-R-N-D and back, pausing 2-3 seconds in each position to fill circuits.
• Leave the engine idling in P.
• When ATF temperature reaches 40°C to 45°C (104°F to 113°F), remove the overflow/level plug using the correct Allen hex bit socket.
• If fluid dribbles out in a thin stream and then slows to a drip, the level is correct.
• If no fluid comes out, add more ATF through the fill port using the fluid transfer pump until it just begins to overflow at the level port.
• Reinstall the overflow/level plug and tighten with a torque wrench: Torque to 20 Nm (15 ft-lbs).
• Tighten the fill plug with a torque wrench: Torque to 39 Nm (29 ft-lbs).
• Pro tip: Temperature window matters—don’t guess.

Step 8: Reinstall undercovers

• Reinstall the undercovers using the 10mm socket and any removed hardware.
• Replace damaged clips using the trim clip removal tool to seat them properly.

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✅ After Repair

• With the engine off, wipe everything clean and check for seepage around the drain/fill/level plugs.
• Test drive 10-15 minutes, then recheck underneath for leaks.
• If you notice delayed engagement, flare, or harsh shifts, stop and re-check level using the same temperature window.
• Dispose of used ATF responsibly (most parts stores accept it).

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💰 DIY vs Shop Cost

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

DIY Cost: $55-$110 (parts only)

You Save: $140-$395 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?

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