Materials needed: Linked products provided for reference.
- 1.40L (2.96 pints) 80W-90 gear oil
- 3/8” rachet
- 1/2” or 13mm hex socket
- 3/8” torque wrench
- Silicone sealant/RTV
- Flat head tool and mallet
- Oil catch pan
- Metal glass scraper razer
- Brake cleaner
- WD-40 penetrant
- Rags or towels
- Gloves and pumice soap
- Oil hand pump
- Spare oil container
I changed the rear axel differential fluid on my 2007 Ford Escape Hybrid with 222k miles. The rear differential fluid has not been changed since it left the factory 15 years ago. This axel has probably been periodically submerged in water from driving through hurricanes in South Carolina and flooded roads in Florida so it’s time to see its condition inside!
Proceed at your own risk! You are recommended to go to a certified dealer to service your vehicle.
- Secure the vehicle on level ground with a lift or equivalent jack stands. This is important for filling it with oil to the correct level.
- Lower the spare tire to make accessing the rear differential easier.
- Place an oil catch pan under the rear differential.
- Remove the rear differential fill plug (3/8” rachet)
- Loosen all 10 cover bolts (13mm or 1/2in hex) located along the edge of the rear differential cover
- Leave the top cover bolt loose and remove the other 9 bolts. Keep the top bolt partly screwed in to prevent oil spilling everywhere when removing the cover.
- Use a flat edge tool and mallet on the edge where the cover meets the casing to break the sealant and pry the cover loose.
- When enough oil has drained, remove the top cover bolt and entire rear differential cover.
- Clean the interior surface and gears. If you have the car in neutral on a lift with parking brake off, you can rotate the wheels by hand to expose hard to clean parts of the rear differential.
- Clean the rear differential cover and ensure that the breather vent is clear and moves freely.
- Clean the rear differential case face that touches the cover. Make sure to get the previous sealant off of both the differential case and cover. A razor glass scraper works well. You can lightly sand the surface all around to get rid of any remaining sealant.
- Clean the fill plug and remove the metal shavings that are stuck on the magnetic bolt.
- Apply silicone sealant in an alternating pattern to the clean differential case face that will seal with the cover. I used Permatex Ultra Black RTV Silicone Gasket Maker but any oil resistant gasket maker sealant should work. The 2007 Ford Escape rear differential is an open differential and power is electronically engaged by the vehicle computer. The rear wheels don’t seem to be engaged full time and the rear differential shouldn’t get as hot as other powertrain components.
- Loosely screw in the 10 cover bolts. Wait 1 hour before tightening to spec if using Permatex Ultra RTV. Tighten cover bolts with a torque wrench to 17 lb-ft.
- Leave the fill hole open and do NOT refill with gear oil yet. WAIT 24 hrs for the sealant to cure. Permatex Ultra RTV calls for 24 hrs of curing and exposure to air. Yes, you can’t drive the car until tomorrow.
- Fill the rear differential through the fill hole with 1.40L (2.96 pints) 80W-90 gear oil. Stop filling when oil drains out from the fill hole.
- Replace the fill plug and tighten fill plug with a torque wrench to 20 lb-ft.
- Drop off the drained oil for recycling at the autoshop or county waste facility.
After driving 1000 miles, my fuel economy increased about 10% from 26-28 mpg. Minimizing resistance in this component of the powertrain may have helped.