🔧 F-350 Super Duty - Transmission Fluid & Filter Service

This job drains the old automatic transmission fluid, replaces the internal filter, and refills the transmission to the correct level. Fresh fluid helps shift quality and protects the transmission from heat and wear.

Assumption: Your F-350 uses the Ford 6R140 6-speed automatic with a pan, replaceable filter, and a fill/level plug method.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• 🛑 Work on a level surface and support the truck with jack stands; never rely on a jack alone.
• 🔥 Transmission fluid can be very hot; let it cool enough to avoid burns.
• 🧯 Keep spills off the exhaust and clean up immediately; ATF is flammable when atomized.
• 🧤 Wear nitrile gloves and safety glasses; ATF will drip from multiple edges.
• 🔌 Battery disconnect is not required for this service.

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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, pair)
• Wheel chocks (pair)
• Safety glasses
• Nitrile gloves
• Drain pan (at least 15-quart)
• 3/8" drive ratchet
• 1/4" drive ratchet
• Socket set (metric)
• Torque wrench (inch-pound)
• Torque wrench (foot-pound)
• Trim clip remover
• Plastic scraper
• Shop towels
• Brake cleaner spray
• Fluid transfer pump (specialty)
• Infrared thermometer

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission filter - Qty: 1
• Transmission pan gasket - Qty: 1
• Automatic transmission fluid (Motorcraft MERCON LV) - Qty: 8-10 quarts
• Drain/fill plug seal or washer - Qty: 1

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📋 Before You Begin

• 🅿️ Park on level ground, set the parking brake, and chock the rear wheels with wheel chocks.
• ⬆️ Raise the front (and ideally the rear) so the truck sits level on jack stands.
• 🌡️ Plan your fluid level check: you’ll need the transmission warm during the final level-set. Use an infrared thermometer to read the transmission pan temperature.
• 🧴 Set out plenty of shop towels; this service is messy.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Safely raise and level the truck

• Place wheel chocks behind the rear tires.
• Lift the truck with a floor jack (rated 3-ton minimum).
• Set it down on jack stands (rated 3-ton minimum, pair) so the truck is stable and level.

Step 2: Remove any splash shield (if equipped)

• Position your drain pan (at least 15-quart) under the transmission area.
• Remove shield fasteners using a socket set (metric) and a trim clip remover.

Step 3: Drain the transmission pan

• Place the drain pan (at least 15-quart) directly under the pan drain area.
• If your pan has a drain plug, loosen it with a ratchet and appropriate socket set (metric) and drain the fluid.
• If there is no drain plug, loosen the pan bolts with a 3/8" drive ratchet and socket set (metric), leaving a few bolts started on one side so you can “tilt” the pan and control the spill.
• Tip: Loosen the rear edge first to aim the stream.

Step 4: Remove the transmission pan

• Support the pan with one hand and remove the remaining bolts using a 3/8" drive ratchet and socket set (metric).
• Lower the pan carefully into the drain pan (at least 15-quart).
• Remove the old gasket. Use a plastic scraper only (metal scrapers can gouge the sealing surface).

Step 5: Replace the transmission filter

• Locate the filter at the valve body (the aluminum assembly above the pan).
• Remove the filter fasteners (if bolted) with a 1/4" drive ratchet and socket set (metric), then pull the filter straight down.
• Make sure the old filter seal/O-ring comes out with the filter (don’t leave it stuck in the transmission).
• Install the new filter, then tighten the fasteners using a torque wrench (inch-pound): Torque to 10 Nm (89 in-lbs).
• Tip: A stuck O-ring can cause a delayed engagement.

Step 6: Clean the pan and reinstall it

• Clean the pan and magnet(s) with brake cleaner spray and shop towels.
• Install the new transmission pan gasket onto the pan.
• Start all pan bolts by hand to avoid cross-threading.
• Tighten pan bolts evenly in a crisscross pattern using a torque wrench (inch-pound): Torque to 10 Nm (89 in-lbs).

Step 7: Refill with MERCON LV ATF

• Locate the transmission fill point:
  • If equipped with a fill plug on the transmission case, remove it using a ratchet and socket set (metric).
  • If equipped with a dipstick tube, remove the dipstick and fill through the tube using a fluid transfer pump (specialty) if needed.
• Add Motorcraft MERCON LV using a fluid transfer pump (specialty).
• Start by adding about 6 quarts (a typical pan-drop amount), then you’ll fine-tune the level in the next steps.

Step 8: Set the final fluid level (fill/level plug method)

• Start the engine and keep your foot on the brake.
• Move the shifter slowly through each gear (P-R-N-D and back), pausing 2-3 seconds in each position.
• With the engine idling, check the transmission pan temperature using an infrared thermometer (aim at the center of the pan).
• When the pan is roughly 35°C–45°C (95°F–113°F), remove the level/check plug (typically in or near the pan) using a ratchet and appropriate socket set (metric).
• Add fluid through the fill point using a fluid transfer pump (specialty) until a thin stream/dribble comes out of the level hole.
• Let it slow to a steady dribble, then reinstall the level/check plug and tighten with a torque wrench (foot-pound): Torque to 35 Nm (26 ft-lbs).
• Tip: Level setting must be done while idling.

Step 9: Reinstall shields and lower the truck

• Reinstall any splash shield using a socket set (metric) and trim clip remover.
• Lower the truck from the jack stands using the floor jack.

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✅ After Repair

• 🔍 With the engine running, inspect for leaks around the pan and plugs.
• 🧪 Road test 10–15 minutes, then recheck for leaks again when parked.
• 🌡️ If shifts feel odd, recheck the fluid level at the same temperature range; being slightly low can cause flare/slip.
• 🧾 Dispose of used ATF at a recycling center; don’t dump it.

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💰 DIY vs Shop Cost

Shop Cost: $350-$650 (parts + labor)

DIY Cost: $120-$250 (parts only)

You Save: $230-$400 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-3 hours.

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🎯 Ready to get started?

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