Rear differential fluid? Amsoil alternative?

[BouncinBrandon]

Greetings, I'm here to inquire about the rear differential fluid for a 2024 Ford Bronco Sport Big Bend 1.5L 3-cyl. I'm an Amsoil guy, and I have compiled a list of Amsoil alternative fluids I'll be switching this new Bronco to, the only issue I seem to be having is with the rear differential fluid. The rear diff seems to call for
Motorcraft XY-75W-QL, but Amsoil doesn't have a recommended alternative on their site. I called tech support, and they stated they don't recommend any of their specific products as none of them perfectly match the specifications. What intrigues me are a few people I've seen on this forum state how they're using Amsoil's 75W-90 Severe Gear lube in the rear diff. Who would recommend using the 75W-90 Severe Gear lube vs the recommended Motorcraft XY-75W-QL? What specs are missing from the severe gear lube vs the OEM recommendation? If you're currently running Amsoil in your rear diff, what's your experience been? Appreciate any replies in advanced!

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[Pacemaker]

I'm also an Amsoil guy. I've done the 30k maintenance that Ford experts recommend. Transmission and transfer case
Of course the engine when due
All with Amsoil
Rear differential is another story
Have to use the Motocraft fluid. The experts say change at 60k
I checked mine..
Full and clear

 

[Mark S.]

that Ford experts recommend

Don't forget: these are the "experts" who get paid to perform maintenance, whether it's necessary or not.

 

[Pacemaker]

These experts are on YouTube. The fluids were dirty as heck. I think I'll go with the 30k recommendations. It drives and shifts better.

 

[BouncinBrandon]

r differential is another story
Have to use the Motocraft fluid.

I guess this is the part I'm skeptical of. Ford likes their proprietary fluids, and I feel like they'll slap some random spec on their fluids just to scare you into buying OEM. Considering there seems to be a few who do use Amsoil in their rear diff on this forum, that leads me to believe you don't have to use the Motorcraft stuff, but I'm interested in hearing the experience from someone who's been using Amsoil in their rear diff just to be safe.

 

[Pacemaker]

I agree with you. Ford still prefers semi synthetic oil.

 

[BouncinBrandon]

I agree with you. Ford still prefers semi synthetic oil.

I wouldn't even call what they push synthetic. I don't believe there's a true OEM synthetic on the market. From what I've researched, most of these OEM fluids are just group 3 base oils, which are just highly refined conventional oils, but companies are legally allowed to call these products synthetic. Boggles my mind, since Amsoil is one of the only true synthetic brands out there. I'm probably gonna gamble on running Amsoil's 75W-90 in the rear diff since others seem to be doing so.

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