Front diff fluid type

[GhostStrykre]

The owner's manual calls for 80w-90 conventional gear oil, regardless if a locker or not.
The only synthetic I found that meets the Ford spec in the owner's manual is Redline 75w-90.
I changed both my axles with that at 30k and will do it again at 100k, which will be before this year is out.
FWIW, Redline D6 ATF meets the Ford spec for the transfer case fluid.

i'm not entirely sure what spec you speak of, so i'll probably take that as a hint to just snag the motorcraft stuff to take my guess work out of it. i'll read up on it in the meantime to educate myself. appreciate it!

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[Canadian Ranger]

i was about to order some gear oil for my first diff fluid change. i was dead set on grabbing some amsoil 80w-90, but noticed it was flagged for having friction modifiers. i don't think that's really needed for my fx4's locking rear diff based on the above, but i also read on a different thread that amsoil isn't actually as good as the motorcraft (here, post #11 really kicks off the discussion: https://www.ranger5g.com/forum/threads/2019-ranger-rear-differential-failure.17021/ )

so now i'm torn. amsoil or motorcraft. or does it really not matter?

I've changed mine twice with Amsoil, no problems. If their website recommends any fluid on their vehicle lookup, it fine to use.

 

[diesel924]

Amsoil refuses to submit their oil for OEM testing. But, they claim OEM compliance. Actually, they only appear to claim OEM compliance. They are very careful about the wording of their claims. "It is recommended for European gasoline or diesel vehicles requiring any of the following performance specifications:" The above claims actually means "Amsoil recommends that you use their product in the following applications but the vehicle manufacturers do NOT recommend for these applications and are confident that their refusal to consider Amsoil product warranty compliant is justified under the Magnus-Moss act" Amsoil does use good base stocks and additives. In fact, they purchase these base stocks and additives from the same oil companies that they compete with (BG likewise purchases their additives from Chevron). Sometimes Amsoil falls short because they use additives that prevent them from meeting OEM requirements. Sometimes they fail because they have the wrong dynamic viscosity. The bottom line is that there are always plenty of outstanding sources of OEM approved products and Amsoil is not one of them. Amsoil reps are trained aggressively to believe otherwise. BG does the same thing. Both BG reps and Amsoil reps will argue that their products can not possibly fail to meet OEM requirements. It simply is not true. But, Valvoline and Castrol are frequently in exactly the same position... (failing to meet OEM requirements while claiming that they do).

 

[Canadian Ranger]

Amsoil refuses to submit their oil for OEM testing. But, they claim OEM compliance. Actually, they only appear to claim OEM compliance. They are very careful about the wording of their claims. "It is recommended for European gasoline or diesel vehicles requiring any of the following performance specifications:" The above claims actually means "Amsoil recommends that you use their product in the following applications but the vehicle manufacturers do NOT recommend for these applications and are confident that their refusal to consider Amsoil product warranty compliant is justified under the Magnus-Moss act" Amsoil does use good base stocks and additives. In fact, they purchase these base stocks and additives from the same oil companies that they compete with (BG likewise purchases their additives from Chevron). Sometimes Amsoil falls short because they use additives that prevent them from meeting OEM requirements. Sometimes they fail because they have the wrong dynamic viscosity. The bottom line is that there are always plenty of outstanding sources of OEM approved products and Amsoil is not one of them. Amsoil reps are trained aggressively to believe otherwise. BG does the same thing. Both BG reps and Amsoil reps will argue that their products can not possibly fail to meet OEM requirements. It simply is not true. But, Valvoline and Castrol are frequently in exactly the same position... (failing to meet OEM requirements while claiming that they do).

That's not a thing. Companies don't submit their oil for OEM testing, because the OEM's don't even blend their own oil. It's a meaningless certification. Or is it because they use additives that prevent them from meeting OEM requirements.......There's only a small handful of companies that produce base stock and additives.....they use the the same ones as everyone else.
I've had several oil analyses done on my used Amsoil, both motor oil & gear fluids and they've told me to extend my drain intervals well past any OEM recommendation. The extra price I pay is far less money then doing multiple fluid changes.

 

[diesel924]

You do you, Boo. If the oil was soooo good, wouldn't they want to wear all the factory certifications it has like a badge of honor? I've heard all of the claims from the Scamsoil salesmen that come to my shop; here's my favorite:
ME: "Sure, I'm open to changing brands of oil. Just show me on the datasheet where it's approved by Ford to WSS-M2C961-A1 and we'll talk turkey".
Salesman: "If we sent all of our oil for testing for the OEM's, we would have to charge a lot higher price!"
ME: "So your oil is cheaper than *fill in the blank* which IS an approved oil?"
Salesman: "Uh, no actually it's 25% higher."
ME: "So you want me to spend MORE to not have the proper certification oil?"
Salesman: "Well a lot of people like our oil!"

How this makes sense if beyond me.

 

[Cmar]

It's true that a lot of companies claim to meet the manufacturer's standard but it's not actually certified. Some Castrol stuff is, ie their Mercon LV IS certified to meet the Ford standard, and it IS comparatively expensive.
However given something generic like a spiral bevel diff you could probably use any oil which meets the specification from any reputable manufacturer without fear, even mineral, if you're going to change it more often. Using limited slip rated oil in an open diff doesn't cause any harm. The other way around however is a no no unless you add the anti chatter additive.

Variability is interesting over here Ford recommend 80W-90 EP synthetic gear oil for both diffs front and back, yet the Mazda BT50 also sold here, which was until recently a Ranger clone, recommended 80W-150 for the rear diff and 80W-90 for the front for the exact same assembly! They also recommended a different range of oils for the same engine.
The BT 50 is no longer a Ranger clone as Mazda and Ford had a falling out, and the new Mazda BT 50 is now based on the Isuzu D Max ute.

 

[Frenchy]

You do you, Boo. If the oil was soooo good, wouldn't they want to wear all the factory certifications it has like a badge of honor? I've heard all of the claims from the Scamsoil salesmen that come to my shop; here's my favorite:
ME: "Sure, I'm open to changing brands of oil. Just show me on the datasheet where it's approved by Ford to WSS-M2C961-A1 and we'll talk turkey".
Salesman: "If we sent all of our oil for testing for the OEM's, we would have to charge a lot higher price!"
ME: "So your oil is cheaper than *fill in the blank* which IS an approved oil?"
Salesman: "Uh, no actually it's 25% higher."
ME: "So you want me to spend MORE to not have the proper certification oil?"
Salesman: "Well a lot of people like our oil!"

How this makes sense if beyond me.

I'm with you here. I know for Motul specifically they have worked with multiple Vehicle Manufacturers in the world to meet the Specifications and be approved. Funny thing about the approval is not every oil is covered by each manufacturer. More like different oils for different manufacturers. This includes the Dexos Rating from GM. Some of their Oils have it and many of the Oils they have do not meet it.

 

[Frenchy]

You do you, Boo. If the oil was soooo good, wouldn't they want to wear all the factory certifications it has like a badge of honor? I've heard all of the claims from the Scamsoil salesmen that come to my shop; here's my favorite:
ME: "Sure, I'm open to changing brands of oil. Just show me on the datasheet where it's approved by Ford to WSS-M2C961-A1 and we'll talk turkey".
Salesman: "If we sent all of our oil for testing for the OEM's, we would have to charge a lot higher price!"
ME: "So your oil is cheaper than *fill in the blank* which IS an approved oil?"
Salesman: "Uh, no actually it's 25% higher."
ME: "So you want me to spend MORE to not have the proper certification oil?"
Salesman: "Well a lot of people like our oil!"

How this makes sense if beyond me.

So for fun I decided to do a quick look. Looks like motul does have oil that meets that particular specification you mentioned along with a few others from Ford. Not saying you're going to switch but I did look.

 

[JohnnyO]

i'm not entirely sure what spec you speak of, so i'll probably take that as a hint to just snag the motorcraft stuff to take my guess work out of it. i'll read up on it in the meantime to educate myself. appreciate it!

It's in the owner's manual in the Specifications & Capacities table.

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