I have a bottle of Redline 75w90ns that i wanted to use in my rear diff. i noticed it DOESNT have the friction modifiers like the regular 75w90 oil. is this good to use in my s2k's diff? i dont want to harm anything.

 

NO! "ns" is NOT a diff fluid. It's meant for manual trannies and it's not even known if it's good for our trannies. We don't need friction modifiers, but FM won't hurt our diffs. DON'T use the "ns" in your rear diff. You will regret it BIG TIME.

 

ok, thanks! should i go with the regular 75w90 Redline then?

 

I'm not sure how many 75W90 fluids Redline makes, but just ensure that it's "GL-5" rated. The "ns" is not a GL-5 fluid.

 

Im just a bit confused because the NS says its a GL-5 "like" fluid. the regular 75w90 says it Exceeds GL-5. so i guess i would be safe going with the Regular 75w-90 or the Superlightweight Shockproof oil then.

 

Hmmm, I just went to the Redline site and read that it's a GL-5 "type" gear lube. You are OK to use it in the diff and although it may be suitable for "some" manual trannies, the fact that it's GL-5 like, it shouldn't go into our trannies as the sulfer content will be detrimental to our trannies. In the same token, it may not have as high a sulfer content as we would like to see for our rear diff application. Go ahead and use it, but you might not want to leave it in there too long and if you track the car or drive it hard a lot, you should consider changing it after a few thousand miles. You may still regret it if used too long. I do know that Redline Shockproof is NOT a good fluid to use in our diffs, yet they promote it as a diff fluid.
Personally, I would prefer a fluid that "exceeds" GL-5 rating over one that is GL-5 "type".
Sorry for getting you confused. Redline is trying to make fluids that have a wide range of applications. As S2000 owners, we must be careful of such fluids.
To re-iterate what I said in my first post, it should not be used in our trannies. One that is acceptable for our rear diff is not a good idea for our trannies.

 

Thanks for clearing that up! i figured you and I were on the same page. im going to use the Regular 75w90. NOT the NS (even though you now say its ok). but like you said, the regular 75w30 EXCEEDS GL-5. its not GL-5 'Like'.

 

Sell the "ns" to someone with a big manual Mustang or some such car to put in their tranny.

 

We only have one UOA of Redline 75W-90 GL-5 gear oil so far. It was posted by rworne in the "Oil Journals" on the "UOA of LE607" thread. It was not the ns stuff or Shockproof stuff. Have a look before you decide to put this product in your differential. Good luck.

 

FWIW that UOA was under par compared to the other UOAs of diff fluid.

stick with mobil 1. good price and easy to find.