Replace transmission fluid and filter on the 10R80 10-speed automatic transmission, ensuring proper fluid level and system function.

Warnings

Tools required

Parts

• Transmission fluid pan gasket × 1 — Use OEM specification
• Transmission fluid filter × 1 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification

Fluids

• Motorcraft MERCON LV ATF — 13 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow transmission to cool to ambient temperature (below 100°F)
3. Raise vehicle securely on jack stands at all four corners, maintaining level position
4. Remove any installed skid plates or underbody panels that obstruct transmission pan access
5. Verify you have correct transmission fluid (Motorcraft MERCON LV) and minimum 13 quarts available

Procedure

1. 1

   Locate and access transmission fluid pan
   Position drain pan under transmission. The fluid pan is located on the bottom of the transmission case, toward the rear of the engine bay. Identify the drain plug on the passenger side of the pan and the fill plug on the driver side of the transmission case.
2. 2

   Drain transmission fluid
   Using a 17mm socket, carefully loosen the drain plug. Allow fluid to drain completely into drain pan - this will take 10-15 minutes. Remove drain plug completely and inspect crush washer for damage. Set aside old crush washer and prepare new one for installation.
   ⚠Initial fluid flow may be strong. Keep hands clear of direct stream to avoid contact with hot fluid.
3. 3

   Remove transmission fluid pan
   Using a 10mm socket, remove all pan cover screws in a crisscross pattern, loosening each gradually. Once all screws are removed, carefully lower the pan. Additional fluid will drain when pan is removed. Clean the pan thoroughly and inspect for metal shavings or debris (small amounts are normal).
   Torque spec

   Cover Screws12 Nm (9 lb-ft)
4. 4

   Remove and replace transmission filter
   Locate the transmission filter attached to the valve body. Remove filter mounting bolts using appropriate socket. Carefully pull filter straight down to remove, being aware that residual fluid will drain. Clean the filter mounting surface on the valve body. Install new filter, ensuring proper alignment and seating of O-rings.
   ℹ️Do not reuse old filter. The 10R80 uses an internal serviceable filter that must be replaced during fluid service.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
5. 5

   Clean and inspect pan gasket surfaces
   Thoroughly clean the transmission pan gasket surface and the transmission case mating surface. Remove all old gasket material using a plastic scraper - do not use metal scrapers that could damage sealing surfaces. Clean both surfaces with brake cleaner and wipe dry with lint-free cloth.
6. 6

   Install new pan gasket and pan
   Position new gasket on transmission pan, ensuring it aligns with all bolt holes. Carefully lift pan into position, aligning gasket with transmission case. Install all cover screws hand-tight first, then torque in a crisscross pattern to specification.
   ⚠Do not overtighten pan screws. Excessive torque will distort the pan and cause leaks.
   Torque spec

   Cover Screws12 Nm (9 lb-ft)
7. 7

   Install drain plug with new crush washer
   Place new crush washer on drain plug. Install drain plug and torque to specification. Verify crush washer is properly seated and not damaged during installation.
   Torque spec

   Oil Drain Plug35 Nm (26 lb-ft)
8. 8

   Add initial transmission fluid
   Locate the transmission fill plug on the driver side of the transmission case (accessed from underneath). Remove fill plug using 8mm socket or Allen key. Using fluid transfer pump, add 6 quarts of Motorcraft MERCON LV ATF through fill hole. This is the initial fill - final level will be set in subsequent steps.
9. 9

   Check for leaks and warm transmission
   Reinstall any underbody panels or skid plates removed earlier. Lower vehicle to ground. Start engine and allow to idle. Observe underneath vehicle for any leaks at pan or drain plug. With engine at idle and foot on brake, shift transmission through all gear positions (P-R-N-D and manual modes), pausing 3 seconds in each position. Return to Park.
   ℹ️Keep vehicle stationary during gear cycling. This circulates new fluid through all transmission circuits.
10. 10

    Set final fluid level at operating temperature
    With engine running and transmission in Park, allow transmission to reach operating temperature (160-180°F). Monitor temperature using scan tool or infrared thermometer aimed at transmission case. Once at temperature, raise vehicle on jack stands while still running. With engine at idle and transmission in Park, remove fill plug. Fluid should drip slowly from fill hole. If no fluid drips, add fluid in 1/2 quart increments until light drip is achieved. If fluid flows steadily, allow excess to drain until only dripping. Install fill plug when correct level is achieved.
    ⚠️Vehicle must be level and securely supported on jack stands with engine running. Ensure proper ventilation and never work under a vehicle supported only by a floor jack.
    ⚠Transmission fluid will be hot during this procedure. Use caution when removing fill plug.

Reassembly

1. Lower vehicle to ground
2. Turn off engine and allow transmission to cool
3. Reinstall any removed underbody panels or skid plates using appropriate fasteners
4. Verify all tools and materials are removed from under vehicle

Verification

• Start engine and verify no transmission fluid leaks at pan, drain plug, or fill plug
• Test drive vehicle for 10-15 minutes, cycling through all gears under normal driving conditions
• Verify smooth shifting with no slipping, harsh engagement, or delayed shifts
• Recheck for leaks after test drive with vehicle at operating temperature
• Monitor transmission temperature during initial drives to confirm normal operating range (160-200°F)

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