Hi All,

I read a statement in one of the posts that I find somewhat confusing and I quote "the differential needs hypoid gear oil". What does this mean exactly?\

I have three Royal Purple Bottles of SAE 75W-90 High Performance Gear Oil. Would this be fine to put in the Honda's S2000 Differential? The last thing I need is to cause any type of unintended damage.

Are there any Amsoil products that are a good fit for the Honda S2000 Differential? Only asking because I found a local guy who carries Amsoil lubricants.

Thank you.

 

Needs correct spec GL<?>
Technical FAQ v2.1 - S2KI Honda S2000 Forums

 

Yes, Amsoil has appropriate products. They have a search function where it asks year make model, then tells you every product they have that works, and which options there are.

For the diff it comes down to that GL rating.

There is some confusion because SAE split the definition of 90W gear oil after S2000 was produced. We need what used to be the upper half of the 90W rating, which is now called 110W.

So when manual says 90w, that now means 110W.

In severe applications, track, high hp, etc, many use 140W.

 

What's confusing about this? From my (and your) owner's manual:Read the label on the oil bottle. If it's GL5 Gear Oil it will say so on the label. Gear oil is different from motor oil. And the SAE grades are measured differently.

Note the SAE 90 spec was changed after our cars were built. It was split into (new) SAE90 -- the bottom half of (old) SAE90 -- and SAE110 -- the top half so either is good. I think the GL6 spec has been obsolete for many years so it's doubtful you'll find any.

Amsoil "severe gear oil" or similar notes GL5 on the fine print on the back of the bottle.
-- Chuck

 

The "GL" number is important. In this case, GL-5. A quick search shows that Royal Purple 75W90 is GL-5 compatible. But read the bottle to make sure.

Weight is the other important thing. 75W90 is fine.

 

As in 75W-110 and probably 75W-140 in hot climates.

-- Chuck

 

So, I have never seen anything about the actual temperature achieved in diffs, ours perhaps, and how much ambient temperature affects internal diff oil temperature.

 

The differential uses a hypoid gear.

Hypoid gears need an oil that can withstand the shearing force from Hypoid gears.

You need a gear oil meant for (any guesses?)
Hypoid gears.

GL5 or GL6 are typical specs used for oils compatible with hypoid gears.

Read the bottle of oil you're holding. It will tell you.

 

An old mechanic told me that the differential can generate a lot of heat. Any gear system that converts one direction of torque rotation to another (two others, in this cane) --- generates a lot of heat. Hotter than most manual transmissions. Proper lubricant is a must.

 

75/140 is a great option for some added cush and protection. I started using it exclusively for the S2k diff years ago being boosted and heavy footed, also with some road course use. It also gets PuddyDads - some may still know who he is) seal of approval.