Redline MT-LV 70W/75W gear oil

[Daox]

I was poking around today looking at different gear oils. My Mirage calls for 75W80 gear oil. The 75W is the engine viscosity when cold, and the 80 is the viscosity when its hot. All oil is substantially thicker when cold, so getting a low first number is a good thing as it will always be thinner when hot. You just don't want it to get too thin, or you can accelerate wear in your transmission. Here is a chart to help illustrate things.





Therefore, I was looking to see if I could get a 70W80 or even 65W80. Alas, I can not find anything like that. However, what I did find was Redline MT-LV 70W/75W. You'll notice this doesn't follow the normal naming convention. So, I'm not exactly sure what to think about it. It is quite a bit thinner than Redline MTL 75W80 that many here have used.





Here are the viscosity specs of the two:

75W/80 (OE spec)
Vis @ 100°C, CSt 10.2
Vis @ 40°C, CSt 50

70W/75W
Vis @ 100°C, CSt 6.5
Vis @ 40°C, CSt 9.8


For reference, 40C is 104F. That already seems warmish for a manual transmission, but I haven't measured my transmission's temperature. Anyway, at 104F, you can see the 70W/75W is 5 times thinner than the 75W80 oil. Thats a heck of a lot less churning going on. Less churning means more efficiency.

Anyways, I post this info because I am thinking about using it in the Mirage. I have contacted Blackstone Labs, a third party oil analysis company. I've asked them how they recommend I proceed with testing this oil with minimal risk to my transmission. I've used them many times in the past for engine oil analysis and they're very helpful.