This procedure covers the removal and replacement of the transmission cooler lines running from the 6R80 automatic transmission to the radiator-mounted cooler on 2011-2014 Ford F-150 trucks with the 5.0L V8 engine.

Warnings

Tools required

Parts

• Transmission cooler line set × 1 — BC3Z-7A031-B or aftermarket equivalent
• Transmission cooler line O-rings/seals × 1 — Included with line set or available separately
• Transmission pan gasket (if inspection required) × 1 — Use OEM specification

Fluids

• Motorcraft MERCON LV ATF — 2 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Allow transmission to cool if vehicle was recently operated (minimum 30 minutes)
3. Raise front of vehicle and support securely on jack stands at frame rails
4. Remove front skid plate if equipped (4WD models typically have factory skid plates)
5. Place drain pans under transmission cooler line connection points at radiator and transmission
6. Have approximately 2 quarts of fresh MERCON LV ATF available for refill

Procedure

1. 1

   Disconnect cooler lines at radiator
   Locate the two transmission cooler lines at the lower passenger side of the radiator. These are quick-connect fittings. Use the appropriate transmission line disconnect tool to release the locking tabs on each fitting. Press the tool over the line and push toward the radiator while pulling the line away. Expect transmission fluid to drain from the lines. Have drain pan positioned underneath.
   ⚠Do not pry or use excessive force on quick-connect fittings. Use proper disconnect tool to avoid damaging radiator cooler ports.
2. 2

   Trace and support cooler lines
   Follow the cooler lines from the radiator back toward the transmission. Note the routing path along the frame rail and any mounting clips or brackets. The lines run along the passenger side frame rail on 4WD models. Remove any retaining clips securing the lines to the frame or body using a flat-head screwdriver or appropriate tool.
3. 3

   Disconnect lines at transmission
   At the transmission case (driver side near the pan), locate the two cooler line fittings. On the 6R80 transmission, these are threaded compression fittings. Use a line wrench (flare nut wrench) to loosen the fittings while holding the transmission port with another wrench to prevent twisting. Turn counterclockwise to remove. Allow remaining fluid to drain into the pan.
   ⚠Use line wrenches rather than open-end wrenches to avoid rounding off the soft aluminum fittings.
4. 4

   Remove cooler lines from vehicle
   Carefully remove the cooler lines from the vehicle, working them out from any remaining clips or brackets. Note the exact routing for installation of new lines. Take photos if necessary for reference. Inspect the old lines for signs of rubbing, chafing, or damage that may have caused failure.
5. 5

   Inspect and clean connection points
   Inspect the cooler ports at the radiator and transmission for damage, debris, or metal shavings. Clean the threaded ports at the transmission using a wire brush and brake cleaner. Inspect the quick-connect ports at the radiator for damage to the O-ring grooves. Replace radiator if ports are damaged. Check for metal debris in fluid which may indicate internal transmission damage.
   ℹ️Metal shavings or debris in the transmission fluid may indicate internal transmission wear and should be investigated further.
6. 6

   Prepare new cooler lines
   Unpack new cooler lines and verify they match the original routing and length. Check that all O-rings and seals are present at connection points. Lightly lubricate the O-rings on the quick-connect ends with clean MERCON LV transmission fluid. Ensure threaded fittings are clean and free of debris.
7. 7

   Route new cooler lines
   Route the new cooler lines along the same path as the original lines, following the passenger side frame rail. Ensure lines are positioned away from exhaust components, sharp edges, and moving parts. Do not connect ends yet. Verify proper routing and that lines will reach both the radiator and transmission without tension or kinking.
   ⚠Ensure cooler lines have adequate clearance from exhaust components and catalytic converters to prevent heat damage.
8. 8

   Connect lines at transmission
   Apply a thin coat of clean MERCON LV fluid to the threads of the transmission cooler port fittings. Thread the cooler line fittings into the transmission ports by hand first to ensure proper thread engagement. Use a line wrench to tighten the fittings snugly. Torque to manufacturer specification, typically 25-30 Nm (18-22 lb-ft) if using factory lines. Do not overtighten as transmission case is aluminum.
   ⚠Transmission cooler port threads are in aluminum case. Overtightening can strip threads. Tighten firmly but do not exceed specification.
9. 9

   Connect lines at radiator
   Push each cooler line firmly into the radiator quick-connect ports until you hear and feel a distinct click indicating the locking tabs have engaged. Gently tug on each line to verify it is securely locked in place. The line should not pull free with moderate force.
10. 10

    Secure cooler lines
    Reinstall all mounting clips and brackets that secure the cooler lines to the frame rail and body. Verify the lines are properly supported and cannot vibrate or contact other components. Double-check clearance from exhaust and suspension components through full range of motion.
11. 11

    Refill transmission fluid
    Locate the transmission dipstick on the passenger side of the engine bay. Remove the dipstick and insert a long-neck funnel. Add approximately 2 quarts of MERCON LV ATF to replace fluid lost during line replacement. Do not overfill at this stage as you will check level with engine running.
12. 12

    Check for leaks and verify fluid level
    Start the engine and allow it to reach normal operating temperature. With the engine running and transmission in Park, check all cooler line connections for leaks at both the radiator and transmission. Shift through all gear ranges (P-R-N-D) while holding the brake, pausing in each gear for 3-5 seconds. Return to Park. Check fluid level on dipstick with engine running. Add fluid as needed to bring level to the proper range on the dipstick. Recheck all connections for leaks.
    ⚠Keep hands and tools clear of moving engine components and cooling fans during leak check.

Reassembly

1. Reinstall front skid plate if equipped, ensuring proper torque on mounting bolts
2. Lower vehicle from jack stands and perform final visual inspection of cooler line routing
3. Test drive vehicle through all gears and recheck fluid level after reaching operating temperature
4. Inspect for leaks again after test drive, paying particular attention to connection points

Verification

• Verify no transmission fluid leaks at radiator or transmission connection points with engine at operating temperature
• Confirm transmission fluid level is within proper range on dipstick with engine running in Park
• Verify smooth shifting through all gears with no slipping or delayed engagement
• Confirm cooler lines are properly secured and have adequate clearance from exhaust and suspension components
• Check that transmission operates at normal temperature range (typically 175-200°F) during normal driving

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