Preferred Gear Oil for Front & Rear Differential

[Ruger]

Given Royal Purple's reputation and easy availability of their products, I'm seriously considering using their Max Gear product for a quickly upcoming service of my front and rear differentials. Is anyone using Royal Purple Max Gear? I note that Max Gear includes a limited slip friction modifier which I am told is not required on my 2011 GEN1, but the company says the product is for open, limited slip, and locking differentials.

http://www.royalpurple.com/product/max_gear/

 

[Ruger]

In the past I have used Amsoil 80w-90 in the front differential and Amsoil 75w-140 in the rear. Royal Purple has 75w-90, not 80w-90. They have 75w-140, though.

I am concerned about the 75w-90 vs. 80w-90 difference, and also about the friction modifier.

Can anyone advise me, please?

 

[MTF]

I put the official Ford Chart in my post refer to that for adding modifier.
I put Mobil 1 in my rear and I'm pleased with it, especially after frying the whole rear years ago.

New updated Ford Official Gear Oil Chart
https://www.fordraptorforum.com/posts/1395576/

 

[Swacer]

In the past I have used Amsoil 80w-90 in the front differential and Amsoil 75w-140 in the rear. Royal Purple has 75w-90, not 80w-90. They have 75w-140, though.

I am concerned about the 75w-90 vs. 80w-90 difference, and also about the friction modifier.

Can anyone advise me, please?

Always gotta watch on the model year of truck too, 75w-140 doesn't apply to all models years.

 

[Ruger]

No friction modifier for the 2011 models, so Royal Purple is not applicable for my truck.
I went with Amsoil again. $20.80 per quart for the 75w-140.
It comes in a big plastic pouch with a nozzle. That turned out to be a lot easier to manipulate in close confines.

I have just shy of 85,000 miles on my truck, and this is the second time I've serviced the differential. The gear oil was noticeably dirty and the magnets (I have the Mag-Hytec differentiql cover) were covered with minute metal particles. Once again my maintenance fanatic habits prove worthwhile.

 

[Deleted member 17706]

No friction modifier for the 2011 models, so Royal Purple is not applicable for my truck.
I went with Amsoil again. $20.80 per quart for the 75w-140.
It comes in a big plastic pouch with a nozzle. That turned out to be a lot easier to manipulate in close confines.

I have just shy of 85,000 miles on my truck, and this is the second time I've serviced the differential. The gear oil was noticeably dirty and the magnets (I have the Mag-Hytec differentiql cover) were covered with minute metal particles. Once again my maintenance fanatic habits prove worthwhile.

Purple Royal will not out perform AMSOIL diff fluid. I run the 75w-140 too.

Most people don’t think about changing their diff and transfer case fluids regularly. I wouldn’t go more than 30k miles on the fluid—especially if you tow and off-road.

AMSOIL put out a service bulletin several years ago which stated you should change your rear diff fluid after 5k miles because that is when most of the break-in and damage occurs: https://www.amsoil.com/techservicesbulletin/drivetrain/tsb dt-2006-06-29 differential oil change after initial break-in.pdf

Also, when changing your rear diff fluid, you need to take the entire cover off. Yes, it is nice having a drain plug, but a ton of fluid is still left in the bottom of the housing. So that could of contributed to why your fluid was so nasty. I also spray all the gears off with brake part cleaner to remove any oxidation and fine particles which may still be on the gears.

Good job staying on top of things!

 

[Flash1034]

Redline makes a fine 75w-85 synthetic gear oil too.

 

[Raptor 2014]

Redline 75/140 is what I use but any of the above oils will work fine. I would prefer to use a heavier oil that 75/90 range unless you are in very cold climates the majority of the time.

 

[Anthony k]

Purple Royal will not out perform AMSOIL diff fluid. I run the 75w-140 too

HAHAHAHA

ok.

“out perform”
The guy from “Pinks” called, he wants his catch phrase back.

what tremendous “performance” advantage does amsoil have over RP......
I’ll wait... and laugh

 

[Flash1034]

Why go thicker if the spec is 75w-85?