Replacing Rear Differential Fluid

April 15, 2005
Written by: E. Long
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Replacing rear differential fluid for Sterling 10.5 Axle on a 2000 Ford Excursion


This "how to" article was performed on a 2000 Ford Excursion but will apply to all other Sterling 10.5" rear axles. The concepts will also apply to virtually any other differential fluid replacement as well.


Differential Fluid on a Ford Excursion should be changed at 150,000 miles. I opted for Amsoil synthetic fluid as a replacement.

Required Tools:

(1) Jack
(2) Jackstands
(1) Razor blade (from utlity knife)
(1) Block of wood (to block front wheels)
(1) Drain pan
(1) 3/8" ratchet
(1) 1/2" deep socket
(1) 1/2" socket (short -- if you have large exhaust)
(1) 1/2" wrench (if you have large exhaust)
(1) Flat-edge screwdriver
(1) Breaker bar

Products needed:

(4) Amsoil Severe Gear SAE 75W-140 (Sterling 10.5" rear)
(3) Amsoil Severe Gear SAE 75W-90 (Dana 50 front)
(1) Amsoil gear oil hand pump (fits Amsoil 1-quart bottles)
(1) Ultra Grey RTV Silicone Gasket Maker
(1) Amsoil Slip Lock (for rear limited slip)

Time Requirements

About 1 hour


1 out of 10 (1 being easiest, 10 being hardest)

Step 1: Jack up rear of vehicle

1.) Jack up rear of vehicle (leave plenty of room for you to work)

2.) Place block of wood in front or behind front wheel (to prevent the vehicle from moving)

3.) Position jackstands under the outer edges of the axle tubes

4.) Remove jack

Step 2: Drain rear differential

1.) Position drain pan below rear differential

2.) Loosen all 12 bolts, then remove lower 6 differential cover bolts (fluid will start to seep out)

3.) Use a flat-edge screwdriver to pry apart the bottom edge of the differential cover from the differential

4.) Fluid will poor out much easier at this point, continue to loosen the rest of the upper bolts

5.) Remove differential cover (pulling the bottom off first to ensure any excess fluid flows out the bottom

Step 3: Remove old gasket & clean differential cover

1.) Remove excess gasket from differential housing with fingers and razor blade

2.) Remove excess gasket from differential cover with fingers and razor blade

3.) Wipe down differential cover

4.) Wipe down differential housing (where the cover mounts)

Step 4: Add gasket maker and reinstall differential cover

1.) Put bead of gasket maker around the differential cover - the goal being to make a complete seal

2.) Carefully re-mount the differential cover (careful not to break the gasket maker seal -- install a single bolt on top and bottom, then reinstall all bolts hand tightening

3.) Let the gasket maker sit for 15 minutes (or the recommended time based on the instructions)

4.) Torque down bolts with 3/8" ratchet & wrench

5.) The gasket maker will seep out of the edges of the differential cover. You can wipe off any excess with a rag

Step 5: Add differential fluid

1.) Remove the plug on the top of the differential with 3/8" ratchet (use breaker bar if necessary)

2.) The plug has a magnet on the end of it. This will have a lot of metal shavings (typical) on it. Remove the metal shavings with a rag.

3.) Add 4 ounces of Amsoil Slip Lock

4.) Using Amsoil pump, prime the pump

5.) Pump 3 quarts of 75W-140

6.) Reinstall plug

7.) Wipe off excess


This is a great DIY project for the weekend. Differential fluid has a unique smell (not pleasant, in other words), so be sure to dispose of it from your drain pan otherwise your garage will acquire this smell if it sits for a couple days.

Additional Questions or Comments?

Do you have additional questions or comments about this install article? Please discuss them in this forum thread.

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