🔧 Transmission Fluid - Drain and Refill

Your Sierra uses a sealed-style automatic transmission, so the fluid level must be set at the correct temperature. The job is mostly a drain-and-refill service, then a precise level check with the engine running.

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

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⚠️ Safety & Precautions

• Work on a level surface only. A correct fluid level depends on the truck sitting flat.
• Transmission fluid gets hot fast. Let the truck cool before opening the drain or fill plug.
• Use jack stands under the frame if you raise the truck. Never rely on a jack alone.
• Keep the engine running only when checking final fluid level.
• A scan tool is strongly recommended to monitor transmission fluid temperature. A scan tool reads vehicle data and helps you set the level correctly.
• Wear safety glasses and gloves. Transmission fluid can splash when draining.

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🔧 Required Tools

You'll need the following tools for this repair:

• 3/8-inch drive ratchet
• 15mm socket
• Torque wrench
• Drain pan
• Fluid transfer pump
• Scan tool
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Safety glasses
• Nitrile gloves
• Shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid (Dexron ULV) - Qty: 7-9 quarts
• Transmission drain plug seal - Qty: 1
• Transmission fill plug seal - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Chock the rear wheels before lifting the truck.
• If the truck has been driven, let the transmission cool until safe to touch.
• Have the scan tool ready so you can watch transmission fluid temperature during the final level check.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and secure the truck

• Use the floor jack to lift the truck high enough to work under it.
• Set it down on jack stands placed under the frame.
• Keep the truck level side-to-side and front-to-rear.
• Level matters for the final fluid check.

Step 2: Locate the transmission drain and fill plugs

• Use a light and inspect the transmission pan area.
• Find the drain plug on the pan and the fill plug on the case.
• Keep the scan tool nearby for the final temperature check.

Step 3: Drain the old fluid

• Place the drain pan under the transmission.
• Use the 15mm socket and ratchet to remove the drain plug.
• Let the fluid drain completely.
• Inspect the old fluid for metal, dark color, or a burnt smell.
• Install a new transmission drain plug seal.
• Torque the drain plug to 18 Nm (13 ft-lbs).

Step 4: Refill with new fluid

• Remove the fill plug with the 15mm socket and ratchet.
• Use the fluid transfer pump to pump in Dexron ULV.
• Start with about 6 to 7 quarts, then stop.
• Install a new transmission fill plug seal loosely for now.
• Do not overfill yet.

Step 5: Warm the transmission and set the level

• Start the engine and keep the truck level.
• Use the scan tool to monitor transmission fluid temperature.
• With the engine idling, add fluid through the fill hole until a small steady stream begins to come out.
• When fluid just starts to dribble out, the level is close.
• Wait until transmission fluid temperature is in the correct service range, then verify the level again.
• Add small amounts as needed until the fluid becomes a slow drip.
• Torque the fill plug to 35 Nm (26 ft-lbs).

Step 6: Lower the truck and check for leaks

• Shut off the engine.
• Use the floor jack to lift the truck slightly, remove the jack stands, and lower it to the ground.
• Wipe the area clean with shop towels.
• Start the engine again and inspect the drain and fill plugs for leaks.

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✅ After Repair

• Take a short test drive and make sure shifts are smooth.
• Recheck underneath for any seepage after the drive.
• If the transmission still shifts oddly, the fluid level may need to be rechecked at the correct temperature.
• Dispose of used fluid at a proper recycling center.

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💰 DIY vs Shop Cost

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

DIY Cost: $70-$160 (parts only)

You Save: $180-$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.