🔧 Impala - Transmission Fluid Drain and Refill

This procedure replaces part of the automatic transmission fluid in your Impala’s 6-speed transmission. A normal service drains roughly 4.5–5.5 litres; the transmission filter is internal and is not replaced during routine fluid service.

Difficulty Level: Intermediate | Estimated Time: 1.5–2.5 hours

Assumption: This procedure is for the stock GM 6T70 automatic transmission.

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⚠️ Safety & Precautions

• ⚠️ Support your Impala level on four jack stands. Never work beneath a vehicle supported only by a jack.
• 🔥 The final fluid-level check requires the engine to run while the transmission and exhaust are hot. Keep hands, clothing, and tools away from moving or hot components.
• 🛑 Apply the parking brake and chock the wheels before lifting.
• 🧤 Automatic transmission fluid can cause skin and eye irritation. Wear gloves and safety glasses.
• 🚫 Use only licensed DEXRON-VI automatic transmission fluid. Do not use universal CVT fluid or DEXRON-III.
• 🔋 Battery disconnection is not required.

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🔧 Required Tools

You'll need the following tools for this repair:

• 2-ton floor jack
• 2-ton jack stands, set of four
• Rubber wheel chocks, pair
• 7mm socket
• 10mm socket
• 11mm socket
• 3/8-inch-drive ratchet
• 3/8-inch-drive extension, 150mm
• Torque wrench, 5–30 Nm range
• OBD-II scan tool with transmission temperature data (specialty)
• Long-neck transmission funnel
• Drain pan, 8-litre minimum
• Graduated measuring container, 6-litre minimum
• Spirit level, 300mm minimum
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• DEXRON-VI automatic transmission fluid - Qty: 6 litres
• Transmission drain-plug seal - Qty: 1
• Transmission fluid-level plug seal - Qty: 1

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📋 Before You Begin

• 📍 Park your Impala on firm, level ground and apply the parking brake.
• 🌡️ Begin with the transmission cool enough to touch safely.
• 📏 Use the graduated container to measure the old fluid. This gives you a safe starting quantity for refilling.
• 🔎 Connect the OBD-II scan tool and confirm it can display Transmission Fluid Temperature. This is the fluid temperature measured inside the transmission.
• ♻️ Arrange for the used fluid to be delivered to an authorized oil-recycling facility.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Lift and Level the Vehicle

• Place the rubber wheel chocks against the wheels before lifting.
• Use the 2-ton floor jack at the specified body lifting points, then support your Impala on all four 2-ton jack stands.
• Place the 300mm spirit level on a flat section of the rocker structure and adjust the stands until the vehicle is level front-to-rear and side-to-side.
• Gently push the vehicle to verify that every stand is stable.
• Level positioning is essential for an accurate fill.

Step 2: Remove the Lower Splash Shield

• Put on the safety glasses and nitrile gloves.
• Use the 7mm socket, 10mm socket, 150mm extension, and 3/8-inch-drive ratchet to remove the lower splash-shield fasteners as equipped.
• Lower the shield and place it aside with its fasteners.

Step 3: Locate the Service Points

• Locate the transmission drain plug at the bottom of the transmission case.
• Locate the fluid-level plug on the transmission case. The level plug establishes the correct fluid height when the transmission is running at the specified temperature.
• From above, locate the transmission fill cap beneath the hood.
• Clean around all three areas with shop towels before opening anything.

Step 4: Drain the Old Fluid

• Position the 8-litre drain pan beneath the transmission drain plug.
• Use the 11mm socket and 3/8-inch-drive ratchet to loosen and remove the drain plug carefully.
• Allow the fluid to drain until it slows to an occasional drip.
• Inspect the drained fluid. Fine grey residue is common, but metal chips, a burnt smell, or milky fluid indicate that professional diagnosis is needed.

Step 5: Measure the Drained Fluid

• Transfer the old fluid from the drain pan into the 6-litre graduated measuring container.
• Record the exact quantity removed.
• Clean the drain plug with shop towels and install a new drain-plug seal.
• Start the drain plug by hand to prevent cross-threading.
• Use the 11mm socket and 5–30 Nm torque wrench to tighten the drain plug to 12 Nm (106 in-lbs).

Step 6: Add the Initial Refill

• Remove the transmission fill cap by hand.
• Insert the long-neck transmission funnel into the fill opening.
• Pour in the same quantity of new DEXRON-VI fluid that was measured during draining.
• Reinstall the fill cap by hand so dirt cannot enter during warm-up.
• Do not add the entire six-litre supply unless that amount was actually removed.

Step 7: Circulate and Warm the Fluid

• Confirm that your Impala is stable, level, and clear of tools before starting the engine.
• Connect the OBD-II scan tool and select Live Data > Transmission > Transmission Fluid Temperature.
• Start the engine and keep your foot firmly on the brake pedal.
• Move the selector slowly through P-R-N-D, pausing approximately three seconds in each position. Repeat twice, then return to Park.
• Let the engine idle until transmission fluid temperature reaches 85–95°C (185–203°F).
• Do not switch off the engine during the final level adjustment.

Step 8: Set the Final Fluid Level

• With the engine idling, selector in Park, vehicle level, and fluid at 85–95°C (185–203°F), place the 8-litre drain pan beneath the fluid-level plug.
• Wear the safety glasses and nitrile gloves. Avoid the hot exhaust.
• Use the 11mm socket, 150mm extension, and 3/8-inch-drive ratchet to remove the fluid-level plug.
• If fluid runs out in a steady stream, allow it to drain until it becomes a slow drip.
• If no fluid emerges, reinstall the plug loosely, remove the fill cap by hand, and use the long-neck transmission funnel to add DEXRON-VI in 200ml increments.
• After each addition, use the 11mm socket and ratchet to remove the level plug again. The level is correct when fluid changes from a thin stream to a slow drip.
• Install a new fluid-level plug seal and start the plug by hand.
• Use the 11mm socket and 5–30 Nm torque wrench to tighten the fluid-level plug to 12 Nm (106 in-lbs).
• Reinstall the transmission fill cap securely by hand.

Step 9: Check for Leaks

• Keep the engine idling and use the safety glasses and a shop towel to inspect around the drain and level plugs.
• Do not place your hands near hot exhaust parts while checking.
• Switch off the engine after confirming there are no leaks.
• Use shop towels to clean any spilled fluid from the transmission case and surrounding components.

Step 10: Reinstall the Splash Shield

• Position the lower splash shield against the underside of your Impala.
• Start every fastener by hand.
• Use the 7mm socket, 10mm socket, 150mm extension, and 3/8-inch-drive ratchet to tighten the fasteners snugly without crushing the plastic shield.

Step 11: Lower the Vehicle

• Use the 2-ton floor jack to lift each end enough to remove the 2-ton jack stands.
• Lower your Impala slowly onto level ground.
• Remove the rubber wheel chocks only after the vehicle is fully supported by its tyres.

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✅ After Repair

• 🚗 Drive gently for 10–15 minutes and verify that shifts are smooth in both light acceleration and deceleration.
• 🔍 Park on clean, level ground and inspect beneath your Impala for fresh red fluid.
• ⚠️ Stop driving if the transmission slips, delays engagement, makes new noises, or displays a transmission warning.
• 🧾 Record the date, odometer reading, fluid specification, and quantity installed.
• ♻️ Transfer the old fluid into sealed containers and take it to an authorized recycling facility. Never pour it onto the ground or into a drain.

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💰 DIY vs Shop Cost

Shop Cost: ₹10,000–₹18,000 (parts + labour)

DIY Cost: ₹5,000–₹9,000 (parts only)

You Save: ₹5,000–₹9,000 by doing it yourself!

Local labour and imported-fluid pricing vary. This repair takes a shop approximately 1–1.5 hours.

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