transmission

Transmission Oil Cooler

for 2017 Ford F-150 3.5L V6 EcoBoost · RWD

Editorial review:Chris Hackleman — Master Technician · 20+ years · Jeff Moore — Master Mechanic · 20+ years

Difficulty

Moderate

Time

1.8 h

Tools

Steps

🔧Does this apply to your car? Depending on trim and options — tow packages especially — your vehicle may have a separate auxiliary transmission cooler, or one integrated into the radiator side tank. Check which setup you have before planning this job: if it's integrated, cooler service happens with radiator replacement instead.

✓Expert-verified. Personally reviewed and approved by OLP's master technicians (Chris Hackleman & Jeff Moore — 20+ years each). Always follow the vehicle's factory service information and torque specs.

This procedure covers removal and replacement of the transmission oil cooler on a 2015-2020 Ford F-150 with 3.5L EcoBoost V6 engine and RWD configuration.

Warnings

⚠Ensure vehicle has cooled completely before beginning work to avoid burns from hot transmission fluid and coolant.

⚠Transmission fluid and engine coolant will drain when disconnecting cooler lines. Have adequate drain pans positioned.

ℹ️The transmission oil cooler on this vehicle is integrated with the radiator assembly on some configurations. Verify cooler type before ordering parts.

Tools required

Socket set (metric)Essential

Torque wrenchEssential

Drain pan (minimum 6 quart capacity)Essential

Jack and jack standsEssential

Line disconnect tool setEssential

Catch basin for coolant/ATFEssential

Pliers

Shop towelsEssential

Funnel

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Parts

Transmission oil cooler assembly × 1 — Use OEM specification
Transmission cooler line O-rings × 4 — Use OEM specification
Transmission oil cooler mounting bolts × 2 — Use OEM specification
Transmission drain plug crush washer × 1 — Use OEM specification if equipped

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Fluids

Motorcraft MERCON LV ATF — 4 qt

Preparation

Park vehicle on level surface and engage parking brake
Allow engine and transmission to cool completely (minimum 2 hours after operation)
Disconnect negative battery cable
Raise front of vehicle and support securely on jack stands
Remove engine skid plate if equipped
Place drain pans under transmission and radiator area

Procedure

1
Drain transmission fluid
Locate the transmission drain plug on the bottom of the transmission pan. Position drain pan underneath and remove drain plug using appropriate socket. Allow fluid to drain completely. Inspect drain plug and crush washer for damage.
Torque spec
Transmission Drain Plug30 Nm (22 lb-ft)
2
Access transmission oil cooler
From underneath the vehicle, locate the transmission oil cooler mounted to the lower radiator support or frame rail. The cooler is positioned forward of the transmission with two cooler lines running to it. Remove any splash shields or guards blocking access to the cooler and mounting points.
3
Disconnect cooler inlet line
Identify the transmission cooler inlet line (coming from transmission). Use appropriate line disconnect tool to release the quick-connect fitting at the cooler. Be prepared for residual fluid drainage. Cap or plug the line to prevent contamination.
⚠Residual transmission fluid under pressure may spray when disconnecting lines. Wear eye protection and have towels ready.
4
Disconnect cooler outlet line
Use line disconnect tool to release the quick-connect fitting for the outlet line (returning to transmission) at the cooler. Allow any residual fluid to drain into pan. Cap or plug the line to prevent dirt intrusion and fluid loss.
5
Remove cooler mounting hardware
Locate the two mounting bolts securing the transmission oil cooler to the frame rail or radiator support bracket. Remove both mounting bolts and retain for inspection. Note the orientation and position of any brackets or spacers.
6
Remove transmission oil cooler
Carefully lower the transmission oil cooler from its mounting position. Maneuver the cooler away from the lines and frame, being careful not to damage radiator or AC condenser. Tilt cooler to drain any remaining fluid into drain pan. Inspect mounting location for debris or damage.
7
Prepare new transmission oil cooler
Unpack new transmission oil cooler and verify it matches the original unit. Install new O-rings on both inlet and outlet ports of the new cooler. Lightly lubricate O-rings with clean MERCON LV ATF to ensure proper sealing. Inspect mounting brackets and transfer to new cooler if necessary.
8
Install new transmission oil cooler
Position new transmission oil cooler into mounting location, ensuring proper alignment with cooler line connections and mounting holes. Verify O-rings are seated correctly in their grooves. Start both mounting bolts by hand to ensure proper thread engagement.
ℹ️Verify which mounting bolt specification applies (23 lb-ft or 52 lb-ft) based on bolt size and location per service manual.
Torque spec
Mounting Bolts31 Nm (23 lb-ft)
9
Connect transmission cooler lines
Remove caps from transmission cooler lines. Firmly push inlet line into cooler port until you hear/feel a distinct click indicating the quick-connect fitting is fully seated. Repeat for outlet line. Gently tug on each line to verify secure connection.
10
Reinstall drain plug and fill transmission
Install new crush washer on transmission drain plug. Thread drain plug into transmission pan by hand, then tighten to specification. Remove transmission dipstick (if equipped) or access fill plug. Add approximately 4 quarts of Motorcraft MERCON LV ATF through fill point. Final level will be verified after circulation.
Torque spec
Transmission Drain Plug30 Nm (22 lb-ft)
11
Reinstall underbody components
Reinstall engine skid plate if equipped. Verify all drain pans are removed from under vehicle. Lower vehicle from jack stands to ground. Reconnect negative battery cable.
12
Circulate fluid and verify level
Start engine and allow to idle. Cycle transmission through all gear positions (Park, Reverse, Neutral, Drive, Low) holding each for 5 seconds. Return to Park. With engine at operating temperature and running, check transmission fluid level per manufacturer procedure. Add fluid as needed to achieve proper level on dipstick or until fluid appears at check plug.

Reassembly

Torque all fasteners to specifications using proper sequence where applicable
Ensure all quick-connect fittings are fully seated and secured
Verify no fluid leaks at cooler connections after initial circulation

Verification

Start engine and verify no transmission fluid leaks at cooler or line connections
Check transmission fluid level with engine at operating temperature per manufacturer specifications
Test drive vehicle through all gears to verify proper transmission operation and shifting
Recheck fluid level after test drive and top off if necessary
Inspect underneath vehicle for any fluid drips or leaks after 24 hours of operation