Looking for alternative to SAE80 API GL-4 Hypoid gear oil for ATV differential

[lwmi4810]

Hello,
I know there are previous topics on this, but looking for a current recommendation. I have a 2001 Yamaha ATV that recommends "SAE80 API GL-4 Hypoid gear oil" for the differentials. So far based on reading here, the closest alternative I have found so far is Redline 75W80. I was also considering Amsoil Severe Gear 75W-90 but I can't confirm it meets all of the requirements. Since the differential uses a little less than a half quart, just looking for the best one for this application.
Thanks for your help!

 

[ceecbtg]

GL4 is not hypoid generally, but there are GL4 with low EP good for hypoid with low-medium forces requirements. From ambiguous brand advise, go with any 80w GL4, 75w80 or 75w85. Redline 75w80 GL4 is TOP option.

 

[kschachn]

@MolaKule

 

[drtyler]

If GL4 is required due to yellow metals in the differential, some GL5 gear oils are safe for yellow metals. HPL and Amsoil Severe Gear are, but double check with them to verify.

 

[MolaKule]

Hello,
I know there are previous topics on this, but looking for a current recommendation. I have a 2001 Yamaha ATV that recommends "SAE80 API GL-4 Hypoid gear oil" for the differentials. So far based on reading here, the closest alternative I have found so far is Redline 75W80. I was also considering Amsoil Severe Gear 75W-90 but I can't confirm it meets all of the requirements. Since the differential uses a little less than a half quart, just looking for the best one for this application.
Thanks for your help!

Is there any way to determine if this is actually a transaxle, a combination of transmission and differential, or a true differential. Maybe an exploded view of this component? Some differentials have Spider Gears which are less loaded than a Hypoid differential and can use GL-4 fluids.

The ambiguous SAE80 API GL-4 Hypoid gear oil spec could cover a lot of territory. Most older gear oils are stated as 80W90 and are almost equivalent to today's 75W110. Is there any way you could have this lube analyzed to determine the addpack signature and viscosity?

Simply because it has an "80" stated does not imply that it is equivalent to a 75W80.

 

[BrianF]

What a out a universal tractor fluid? Those usually carry GL4.

 

[lwmi4810]

Is there any way to determine if this is actually a transaxle, a combination of transmission and differential, or a true differential. Maybe an exploded view of this component? Some differentials have Spider Gears which are less loaded than a Hypoid differential and can use GL-4 fluids.

The ambiguous SAE80 API GL-4 Hypoid gear oil spec could cover a lot of territory. Most older gear oils are stated as 80W90 and are almost equivalent to today's 75W110. Is there any way you could have this lube analyzed to determine the addpack signature and viscosity?

Simply because it has an "80" stated does not imply that it is equivalent to a 75W80.

I'm certain that the OEM fluid has been changed as we are not the original owners of this ATV so I don't have a way to verify what is in it is even correct anyway. Basically at this point I'm looking to just do a complete lube change as we just got it and no idea when it was changed last.

 

[MolaKule]

I'm certain that the OEM fluid has been changed as we are not the original owners of this ATV so I don't have a way to verify what is in it is even correct anyway. Basically at this point I'm looking to just do a complete lube change as we just got it and no idea when it was changed last.

Well, here is one possibility

https://cdn.prod.website-files.com/6573812bd75b3c4083c0b12a/6642557935020f83d04a780d_amsoil-atv-utv-transmission-data.pdf

The viscosity is that fluid is of a 90 grade (15.5 cSt), but apparently there are others from about 7.3 cSt on up to 15 cSt.

Possibly @Pablo can further assist you.

 

[lwmi4810]

Well, here is one possibility

https://cdn.prod.website-files.com/6573812bd75b3c4083c0b12a/6642557935020f83d04a780d_amsoil-atv-utv-transmission-data.pdf

The viscosity is that fluid is of a 90 grade (15.5 cSt), but apparently there are others from about 7.3 cSt on up to 15 cSt.

Possibly @Pablo can further assist you.

This one looks very interesting, I just noticed that Amsoil now has a vehicle lookup for ATVs, never knew that. And on there it lists this very same item for the differentials on the ATV we have. Thanks for this, so far this seems like a good way to go.

 

[ripcord]

https://www.partzilla.com/catalog/yamaha/atv/2001/big-bear-4wd-yfm40fn/front-differential

 

[MolaKule]

https://www.partzilla.com/catalog/yamaha/atv/2001/big-bear-4wd-yfm40fn/front-differential

Looks like a 90 degree differential so a GL-5 with a 15cSt lube should be sufficient.

 

[lwmi4810]

Looks like a 90 degree differential so a GL-5 with a 15cSt lube should be sufficient.

Thank you for your help on this, I am going to try the Amsoil ATV/UTV Transmission & Differential fluid and see how it goes. I already had my eye on their 4-stroke 0w-40 oil anyway for the engine.

 

[lwmi4810]

FYI , this is the rear gearcase housing that appears to use a ring gear, hoping that is also OK going with the Amsoil ATV Differential fluid (Amsoil shows it is compatible, but wanting to verify here, too): https://www.partzilla.com/catalog/yamaha/atv/2001/big-bear-4wd-yfm40fn/drive-shaft

Thank you again.

 

[MolaKule]

@lwmi4810 The drive pinion to ring gear is still at 90 degrees so the ATV/UTV fluid should be sufficient.

Here is some background on spiral bevel gears and explains the difference between a simple spiral bevel gear system and a Hypoid differential:

Spiral bevel gear - Wikipedia

en.wikipedia.org

"...A hypoid is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The shape of a hypoid gear is a revolved hyperboloid (that is, the pitch surface of the hypoid gear is a hyperbolic surface), whereas the shape of a spiral bevel gear is normally conical. The hypoid gear places the pinion off-axis to the crown wheel (ring gear) which allows the pinion to be larger in diameter and have more contact area. In hypoid gear design, the pinion and gear are practically always of opposite hand, and the spiral angle of the pinion is usually larger than that of the gear. The hypoid pinion is then larger in diameter than an equivalent bevel pinion.

A hypoid gear incorporates some sliding and can be considered halfway between a straight-cut gear and a worm gear. Special gear oils are required for hypoid gears because the sliding action requires effective lubrication under extreme pressure between the teeth..."

 

[Overfill]

From the parts diagram, these look to have intersecting axiis, so my bet is that it uses a bevel gear, which only needs GL-4. GL-5 won't do any harm, though.

Somewhat related: https://bobistheoilguy.com/forums/threads/honda-shadow-differential.381279/