Amsoil severe gear vs Amsoil long life diff fluid?

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Apr 3, 2021
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I have a 2022 4Runner and Deciding which diff fluid to use. I was about to purchase the severe gear in 75w90 but then saw they offer a long life synthetic diff fluid. does anyone have experience with the long life synthetic diff fluid? Since my 4Runner has an open diff in the rear I would prefer to use a diff fluid that doesn’t have a friction modifier already added. The amsoil long life synthetic fluid doesn’t seem to have a friction modifier in it so Im now considering that. Am I being too picky trying to find a diff fluid without friction modifiers in it? Seems like everything sold now days has a friction modifier in it. I know you can use friction modifiers in an open diff but I have read some threads that mention some drawbacks of quicker oxidation.
 
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I have a `18 4Runner and am in the same boat. Will wait until around 30,000 miles and change the diff's and transfer case.

Amsoil recommends the Severe Gear. Looks like the Long Life 75w-90 is better suited for over the road trucks.
 
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I put some of this gear lube in my son's Suzuki 4x4 front and rear diff as well as the transfer case about five years ago. Stil running nice and quiet.

gear oil.jpg
 
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I had this exact question about the Amsoil gear oils. They have the severe gear product and the long life product and the cost difference is several dollars per quart.

I took my question to Amsoil to ask them why I should choose the severe gear over the long life and their reply was interesting. The application for the two products is different. The severe gear is targeted to the non-commercial vehicle owner while the long life product is targeted toward the large trucks and OTR heavy-duty applications. I asked why that would matter and their answer was that the severe gear product is designed around the idea that the common light duty vehicle has a small sump and generally a lighter duty load while the long life product target application is for very large sump differentials of extremely high load applications.

In summary, the long life is best suited to large trucks with huge differential sumps and the severe gear is for vehicle that hold only a few quarts of oil. The severe gear is the higher quality product and likely worth the $2.30 more per quart that they charge.
 
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Just changed front and rear diffs in my wifes 2021 4runner pro. Used Amsoil Severe Gear 75w-90. Front diff was clean and the rear was really dark but only 15,000 miles with little 4wd use. Took almost exactly 5 qts to do drain and fill. Will do the Transfer case at probably 50,000.
 
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Visit a diesel shop and use Delvac 75w90:

Longlife used to have an 80w90.... now see that severegear has the 80w90 option. Is Amsoil vague or blunt concerning no LS additive? Just add 'if' you get chatter.

I don't think sump size will make a difference when something is GL-5 rated, its GL-5 rated. So, best suited is meaningless Amsoil speak.

Which one is GOJ+? That is what I'd use. Or, pick a manufacturer that states no LS additive or definitely needs it for LS.



 

Jmcgrady1994

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Apr 3, 2021
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I had this exact question about the Amsoil gear oils. They have the severe gear product and the long life product and the cost difference is several dollars per quart.

I took my question to Amsoil to ask them why I should choose the severe gear over the long life and their reply was interesting. The application for the two products is different. The severe gear is targeted to the non-commercial vehicle owner while the long life product is targeted toward the large trucks and OTR heavy-duty applications. I asked why that would matter and their answer was that the severe gear product is designed around the idea that the common light duty vehicle has a small sump and generally a lighter duty load while the long life product target application is for very large sump differentials of extremely high load applications.

In summary, the long life is best suited to large trucks with huge differential sumps and the severe gear is for vehicle that hold only a few quarts of oil. The severe gear is the higher quality product and likely worth the $2.30 more per quart that they charge.
Thanks for the feedback! I went to purchase some amsoil severe gear from their website but looks like they are out of stock in my area. I’ll have to search around for another distributor.
 

Jmcgrady1994

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Just changed front and rear diffs in my wifes 2021 4runner pro. Used Amsoil Severe Gear 75w-90. Front diff was clean and the rear was really dark but only 15,000 miles with little 4wd use. Took almost exactly 5 qts to do drain and fill. Will do the Transfer case at probably 50,000.
When you did the diffs on your 4Runner, did you fill them up until they started dripping from the fill hole?
 
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When you did the diffs on your 4Runner, did you fill them up until they started dripping from the fill hole?
Yes sir. I believe Toyota says 0-5mm from the fill hole. I just fill till it drips out and close it up. I used my Motive 1735
which makes this a breeze.
 
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I have a 2022 4Runner and Deciding which diff fluid to use. I was about to purchase the severe gear in 75w90 but then saw they offer a long life synthetic diff fluid. does anyone have experience with the long life synthetic diff fluid? Since my 4Runner has an open diff in the rear I would prefer to use a diff fluid that doesn’t have a friction modifier already added. The amsoil long life synthetic fluid doesn’t seem to have a friction modifier in it so Im now considering that. Am I being too picky trying to find a diff fluid without friction modifiers in it? Seems like everything sold now days has a friction modifier in it. I know you can use friction modifiers in an open diff but I have read some threads that mention some drawbacks of quicker oxidation.
Hopefully @Pablo will see this and jump in!
 
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I wanted to wait until pablo chimed in. But i had the rear end of my previous truck rebuilt from being a g80 and it didn't need a friction modifier anymore, I used Severe gear 75w140 without issue.
 
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