🔧 Transmission Fluid - Drain and Refill

Your Sierra uses a sealed-style automatic transmission fill procedure, so the fluid level must be set at the correct temperature. The job is straightforward, but getting the final level right is the important part.

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

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⚠️ Safety & Precautions

• Transmission fluid gets very hot. Let the truck cool before opening anything.
• Keep the truck level when checking the final fluid level.
• Use jack stands on solid ground. Never rely on a jack alone.
• Do not overfill. Too much fluid can cause shifting problems and leaks.
• A scan tool is strongly recommended to read transmission fluid temperature for the final level check.

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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
• 15mm socket
• 10mm socket
• Ratchet
• Torque wrench
• Fluid transfer pump
• Flat-blade trim tool
• Scan tool
• Shop rags
• Funnel

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid - Qty: 5-7 quarts
• Transmission pan gasket - Qty: 1
• Transmission filter - Qty: 1
• Transmission pan bolts - Qty: 1 set, replace if damaged

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📋 Before You Begin

• Park on a flat surface and set the parking brake.
• Chock the rear wheels if lifting the front.
• Raise and support the truck so it stays level.
• If you are replacing the filter, be ready for a mess when the pan comes off.
• Have the scan tool ready to read transmission fluid temperature.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Warm and prepare the truck

• Start the engine and let it idle for a few minutes, then shut it off.
• Raise the truck with a floor jack (rated 3-ton minimum) and support it with jack stands (rated 3-ton minimum).
• Make sure the truck is level side to side and front to back.

Step 2: Remove the skid plate or splash shield

• Use a 10mm socket and ratchet to remove the fasteners holding the lower shield, if equipped.
• Set the shield aside.

Step 3: Drain the transmission fluid

• Place a drain pan under the transmission pan.
• Use a 15mm socket and ratchet to loosen the pan bolts.
• Loosen the rear bolts first and let the fluid drain from one corner.
• Leave a few bolts threaded in loosely.
• Once the flow slows, support the pan and remove the remaining bolts.

Step 4: Replace the filter and gasket

• Lower the pan and pour out the remaining fluid.
• Remove the old filter with your hand. Some fluid will spill.
• Install the new transmission filter by pushing it into place.
• Clean the pan thoroughly with shop rags.
• Install the new transmission pan gasket on the pan.

Step 5: Reinstall the pan

• Hold the pan in place and start all bolts by hand.
• Use a 15mm socket and ratchet to snug the bolts in a crisscross pattern.
• Torque to 12 Nm (106 in-lbs).

Step 6: Fill with new fluid

• Locate the transmission fill plug on the side of the case.
• Use a fluid transfer pump to add new automatic transmission fluid through the fill hole.
• Add about 4 quarts first, then stop.
• Reinstall the fill plug finger-tight for now.

Step 7: Set the final fluid level

• Start the engine and keep it idling.
• Use the scan tool to read transmission fluid temperature.
• With your foot on the brake, shift slowly through each gear, then back to Park.
• When fluid temperature is in the proper range, remove the level check plug, if equipped, or verify level at the fill/check opening depending on transmission version.
• Add fluid slowly with the fluid transfer pump until a small steady stream drips from the check point.
• Stop as soon as it turns to a drip.
• Install the plug and tighten it securely.

Step 8: Reinstall shields and lower the truck

• Reinstall the shield with a 10mm socket and ratchet.
• Lower the truck carefully.

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✅ After Repair

• Start the engine and check for leaks at the pan and plugs.
• Test drive the truck gently.
• Make sure shifts are smooth and the transmission does not flare or slip.
• Recheck the fluid level only when the transmission is at operating temperature.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $70-$170 (parts only)

You Save: $150-$250 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.