2012 rear differential quantity & additive verification

[hessell1114]

Happy Thanksgiving!

After researching on these forums, YouTube, and the manual I can not seem to find out if I need to add the friction modifier. I am going to drain and pump fill the rear differential with:
**XY-75W140-QL-SAE 75W-140 (is buying three quarts enough?)
**Additive XL-3 Friction Modifier ( it comes in a 4oz bottle, but not sure how much you add to the differential?) Is it an amount per quart or just one per differential?

2012 Expedition 4×4 Limited

Thank you,

Tom

 

[99WhiteC5Coupe]

Happy Thanksgiving!

After researching on these forums, YouTube, and the manual I can not seem to find out if I need to add the friction modifier. I am going to drain and pump fill the rear differential with:
**XY-75W140-QL-SAE 75W-140 (is buying three quarts enough?)
**Additive XL-3 Friction Modifier ( it comes in a 4oz bottle, but not sure how much you add to the differential?) Is it an amount per quart or just one per differential?

2012 Expedition 4×4 Limited

Thank you,

Tom

When I changed the rear differential fluid on my 2015 Expedition Limited (does not have the limited-slip differential) it took about 2.3 or 2.4 quarts to fill.

When changing other vehicles, the 4 oz. bottle of limited-slip additive was the correct amount.

Make sure you have the limited-slip differential, as some years it was optional or not available.

I also replaced the two drain and fill plugs (same parts). They are tight, and held in place with red thread sealer. I used a hand-held propane torch to quickly warm the plugs, and they twisted out easily. Ford sells new plugs with the thread sealer on them. If you want me to post the part number, let me know.

 

[71Rcode]

I didn't use any friction modifier in my 2011 as I don't think it's a limited slip. Just the oem diff fluid

 

[jr1under]

The link below from FordTechMakuloco shows how to find out if you have a limited slip diff. In the comments he says "You can add friction modifier to any axle and no harm will be done but if you don't add friction modifier and the differential ends up being a limited slip unit, damage will occur. So if you are still unsure if your axle requires friction modifier after this video it is better to be safe than sorry and just add one entire bottle."

https://www.youtube.com/watch?v=TKRqnQHfVXA&t=182s

 

[hessell1114]

Thank you for all the quick replies and information. Could you please post the part number to the plugs when you get a chance? Thank you.

 

[99WhiteC5Coupe]

Thank you for all the quick replies and information. Could you please post the part number to the plugs when you get a chance? Thank you.

The Ford OEM part number (package of one) is:

5R3Z-7860108-AA.