🔧 Transmission Fluid - Drain and Fill Service

This service removes old ATF and replaces it with fresh fluid to help shifting stay smooth and protect the transmission. On your Sierra, the fluid level must be checked at the correct temperature, so the fill step matters just as much as the drain step.

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

---

⚠️ Safety & Precautions

• Hot transmission fluid can burn skin. Let the truck cool before starting.
• Work on level ground only. The fluid level check depends on the vehicle being level.
• Use jack stands if you raise the truck. Never rely on a jack alone.
• Keep hands clear of the exhaust and transmission case while the vehicle is running for the level check.
• A scan tool or temperature display is needed to verify fluid temperature during the final level check.

---

🔧 Required Tools

You'll need the following tools for this repair:

• 3/8-inch drive ratchet
• 8mm socket
• 15mm socket
• Torque wrench
• Fluid pump or hand pump
• Drain pan
• Floor jack (rated 3-ton minimum)
• Jack stands
• Safety glasses
• Nitrile gloves
• Scan tool with transmission temperature display
• Shop towels
• Funnel

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid meeting GM Dexron VI spec - Qty: 6-7 quarts
• Transmission pan gasket - Qty: 1
• Transmission filter - Qty: 1
• Transmission pan bolts - Qty: 1 set if replaced

---

📋 Before You Begin

• Park on a level surface and set the parking brake.
• Let the transmission cool to a safe temperature before draining.
• Raise and support the truck level if needed for access.
• Have the scan tool ready before you start the final fill check.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and secure the truck

• Use the floor jack and jack stands to raise the truck high enough to reach the transmission pan.
• Make sure the truck stays level for the fluid level check later.
• Level stance matters here.

Step 2: Drain the transmission fluid

• Place the drain pan under the transmission pan.
• Use the 15mm socket to remove the drain plug, if equipped.
• Let the fluid drain fully.
• Reinstall the drain plug finger tight for now.

Step 3: Remove the transmission pan

• Use the 3/8-inch drive ratchet and 8mm socket to remove the pan bolts.
• Lower the pan carefully. A little fluid will still be inside.
• Clean the pan and magnet with shop towels.

Step 4: Replace the filter and gasket

• Remove the old filter by hand.
• Install the new transmission filter.
• Install the new transmission pan gasket on the pan.
• Raise the pan into position and start all bolts by hand.

Step 5: Reinstall and torque the pan

• Use the 8mm socket and torque wrench to tighten the pan bolts evenly in a crisscross pattern.
• Torque to 12 Nm (106 in-lbs).
• Install the drain plug and torque to 20 Nm (15 ft-lbs).

Step 6: Add initial fluid

• Use the fluid pump or funnel to add about 5 quarts of automatic transmission fluid meeting GM Dexron VI spec through the fill port.
• Install the fill plug finger tight.

Step 7: Warm up and circulate the fluid

• Start the engine and keep the truck level.
• With your foot on the brake, move the shifter slowly through each gear position and pause for a few seconds in each one.
• Return to Park.
• Check for leaks under the pan.

Step 8: Set the final fluid level

• Use the scan tool with transmission temperature display to watch fluid temperature.
• When the fluid reaches the correct fill-check range, remove the fill plug.
• Add fluid with the fluid pump until a thin stream just begins to dribble out of the fill hole.
• Install the fill plug and torque to 38 Nm (28 ft-lbs).
• Overfilling causes shift problems.

---

✅ After Repair

• Lower the truck and test drive it gently.
• Check for leaks again after the drive.
• Verify smooth shifts through all gears.
• If the fluid was badly contaminated, recheck the level again after the first heat cycle.

---

💰 DIY vs Shop Cost

Shop Cost: $220-$450 (parts + labor)

DIY Cost: $90-$180 (parts only)

You Save: $130-$270 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.

---

🎯 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.