🔧 Transmission Fluid - Drain and Refill

On your F-150, the automatic transmission uses a sealed-style fill procedure and the fluid level must be set at the correct transmission temperature. The safest DIY service is a drain-and-refill with the correct Mercon LV fluid, not a flush.

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

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⚠️ Safety & Precautions

• The transmission and fluid can get very hot. Let it cool before opening any drain or fill plugs.
• Keep the truck level during the final fluid-level check.
• Do not overfill. Overfill can cause shifting problems and leaks.
• This procedure requires checking fluid temperature with a scan tool.
• Set the parking brake and use wheel chocks.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands
• Wheel chocks
• Drain pan
• Fluid transfer pump
• 1/4-inch drive ratchet
• 8mm socket
• 10mm socket
• Torque wrench
• Scan tool with transmission temperature display (specialty)
• Safety glasses
• Nitrile gloves
• Shop rags

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• MERCON LV automatic transmission fluid - Qty: 13 quarts
• Transmission pan gasket - Qty: 1
• Transmission filter - Qty: 1
• Transmission pan drain plug seal - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Chock the rear wheels.
• Raise and support the truck level on jack stands if you need access underneath.
• Have the scan tool ready to read transmission fluid temperature.
• Work with the engine off until the final level check.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Warm the transmission slightly

• Drive the truck for 10-15 minutes, or let it idle until the transmission is warm but not hot.
• Warm fluid drains more completely.

Step 2: Raise and secure the truck

• Use the floor jack (rated 3-ton minimum) and support the truck with jack stands.
• Keep the truck level front-to-rear and side-to-side.

Step 3: Drain the transmission fluid

• Place a drain pan under the transmission pan.
• Use the 8mm socket and 1/4-inch drive ratchet to remove the drain plug, if equipped.
• Let the fluid drain fully.

Step 4: Remove the transmission pan

• Use the 8mm socket to remove the pan bolts.
• Lower the pan carefully and pour out any remaining fluid.
• Clean the pan thoroughly with shop rags.

Step 5: Replace the filter

• Use the 10mm socket if needed for any filter fasteners on your transmission setup.
• Remove the old filter and install the new transmission filter.
• Make sure the filter seal seats fully.

Step 6: Reinstall the pan

• Install the new transmission pan gasket.
• Reinstall the pan by hand first, then snug the bolts in a crisscross pattern with the torque wrench.
• Torque to 10 Nm (89 ft-lbs) for the pan bolts. If your pan uses different fasteners, follow the same even pattern and do not overtighten.

Step 7: Add the new fluid

• Use the fluid transfer pump to add MERCON LV automatic transmission fluid through the fill port.
• Start with about 5-6 quarts, then add more after the initial refill.

Step 8: Set the fluid level

• Start the engine with the truck still level.
• With your scan tool with transmission temperature display (specialty), monitor transmission fluid temperature.
• Cycle the shifter slowly through all gear positions, then return to Park.
• At about 85-113°F (29-45°C), remove the fill plug and add fluid until it just begins to drip out in a thin stream.
• Reinstall the fill plug and Torque to 35 Nm (26 ft-lbs).
• Use a thin drip, not a stream.

Step 9: Check for leaks

• Inspect the pan, drain plug, and fill plug for leaks while the engine is running.
• Lower the truck and road test it gently.

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✅ After Repair

• Recheck for leaks after the road test.
• Confirm smooth shifting through all gears.
• If shifting feels odd, recheck fluid level at the proper temperature.
• Dispose of used fluid at a recycling center.

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💰 DIY vs Shop Cost

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

DIY Cost: $90-$170 (parts only)

You Save: $160-$280 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.