Does anyone know the difference between Redline 75w90 and 75w90NS? The 'regular' 75w90 is what I put in the rear diff during my last change. Reading the info online says it's not for manual transmissions due to issues with the synchros...I assume it's fine for the diff. Then there is the 75w90NS which is listed under manual transmission fluids but is GL-5 which is rear diff compatible. The description for the NS also seems to talk more about LSDs and improving locking ability. (in contrast to an earlier post saying it's not hypoid gear compatible)

Thoughts?

As far as I know there is just a friction modifier added for LSDs with the NS version. Other than that they are both GL-5 fluids (which is why you don't use them in your GL-4 tranny).

Any word on the NS version of the Redline? Im about to do my interval change and thinking of leaning towards (NO NS) because our factory ones dont need friction modifier when replacing.

What is the interval for changing this?

Interval is usually 30k miles I think. Final word I got is to NOT use the NS version.

thanks Spearfish....

Just Changed My Rear Differential Oil
 

I just changed my Rear Differential Oil today with the help of this thread! My Z has 4,000 miles on it.

Thanks to SpearFish and (Jeff) Schrute for helping a brother out.

By the way, I am most likely the biggest noob when it comes to cars on this forum. I've always paid an arm and a leg to get my maintenance done on my other cars. Now it's time to do it myself and save some money! Everyone has to start somewhere.

My point is, don't feel discouraged to do this. It is very easy and if I can do it, so can you! :tup: (I changed my engine oil a couple weeks back, that was also very easy too!)

Anways...

Here's a picture of the old rear differential oil (left side) that came from my 370Z and the new RedLine 75W90 oil (right side). Looking at the difference, I am so glad that I changed the rear differential oil now than later!

Might I also suggest using a battery powered siphon pump. I bought mine from Amazon, this is the exact one I got (there are cheaper ones): I think battery powered is easier than air pump powered. It was so easy for me to pump the new oil back in with this: Amazon.com: Sierra Tools JB5684 Battery Operated Liquid Transfer Pump: Home & Garden

I hope my post helped. It's the least I can do! Thanks! :tup:

I'm lost... what is the NS version? I see two different 75W90s on Redlines site, one is the regular and one is their shockproof version. Which one do I not get?

Here is the pump I'll be using next. Easy to clean, easy to use.
fluid transfer pump

Anyone?

Their shockproof line is something I hadn't seen before. I would just continue using the 75W90 GL-5 oil they offer for the rear diff.

I bought this fluid transfer pump and it didnt work at all for me.

Amazon.com: Sierra Tools JB5684 Battery Operated Liquid Transfer Pump: Home & Garden

So I just bought a standard hand pump and that did the job.

There are several different versions of the Redline Fluid and they cover a wide range of uses and abuses.

The Redline 75W90 NS actually lacks some of the friction modifiers found in the regular 75W90 which makes it less slippery and ok to use in a transmission and more aggressive in a differential. That does not mean use it! Please keep reading.......

We have been using Redline for some time at the shop and the fluids we use for the following applications are....
We use the normal 75W90 as Spearfish and several others have already stated for the differential. You can find it on our site HERE.
We have recently begun using Redline's MT-85 for transmission fluid. We have been using the MT-90 in 300ZX's for some time but this fluid did not work well in 350Z and 370Z's. Redline specifically lists this fluid for use in the 370Z. You can see it on their site HERE. I really appreciate a customer and forum member for pointing this fluid out to us. The MT-85 fluid can be found on our site HERE.

Finally you can find the metal washers for the drain plugs on our site HERE.


This is what we have found works well in the majority of 370Z applications. If you are using your car for some extreme application you may want to look into another Redline fluid for your car but so far these fluids have worked well.

I agree with this and have used these fluids in my car. So far no issues. The tranny fluid does make the shifting smoother and easier esp at cold temps.

This is SOOOOO true! :roflpuke2: