Gear and Transmission Oil Questions

[Jordan]

So I just changed my gear oil (used Red Line gear oil 75W90) and the transmission oil (Penzoil multivehicle ATF).  I've since noticed that there are two Red Line 75W90 gear oils.  One is just 75W90 and the other is 75W90NS.  The NS has a special formulation for non limited slip differentials while the non NS has a formulation for limited slip differentials.  My car has a non limited slip differential so do I need to change the oil again to the NS formulation?

Second question.  Can I use the Red Line in the transmission as well.  I know other car manufacturers (Alfa for one) allow Red Line to be used as both gear oil and transmission oil so I wanted to know if anyone else has used it and/or is it OK to use it in place of multivehicle ATF?

[bogeyman]

Marcus:
My only experience with this was when I had an '88 BMW 735I 5 speed with a limited slip diff. One time when I took it to the dealer for service
they replaced the diff fluid with the wrong type. It was apparent almost immediately that something was wrong as I was getting noises from
the differential. When I took it back in they acknowledged that they had used the wrong fluid. After replacement everything was back to normal.

[Benz Dr.]

You want to use only ATF in the trans. Gear lube has additives that can harden the face of the gears which could cause chipping. ATF won't do that and is what you want to make the brass syncro rings work. 

[Kevkeller]

That’s interesting to hear.  My original 4 speed manual had a bearing fail and trash a shaft.  I was able to find another here in Honolulu that had used oil instead of ATF. I corrected the fluid but do have metal flaking going on with it now.

I am looking for another one if someone has a source.

[Jordan]

Thanks for the comments.  Has anyone used Red Line for their gear oil and if so which one did you use?  I haven't yet driven the car since changing the oils (got 30cm of snow last Friday night) so I'm hoping someone can tell me I don't need to change it again (from non NS to the NS version).

[Jordan]

So I e-mailed Red Line and asked about using the non NS and NS 75W90 gear oil in an open differential.  Their site recommended the non NS 75W90 even though the bottle itself says the NS is for open diffs and the non NS is for limited slip diffs. 

Anyway this is the reply I got: "Thank you for contacting Red Line Oil, in your Mercedes Benz open differential the 75W90 would be recommended as the friction modifier contained is beneficial for friction and temperature reduction. The 75W90NS could be used in an open differential, would be suitable though not the first choice."

So I guess I don't need to change the oil again.

I would be interested in knowing what brands and viscosities others are using for gear oil.