100C viscosity of a "75W" oil

[JHZR2]

Can anyone comment on the operating temperature viscosity of a "75w" gear oil? This would be a VW MT oil.

Not a 75w-80 or 75w-90, just "75W". A product like Fuchs Titan Sintofluid FE.

since 75w is a cold temp spec, can you absolutely just go across the viscosity chart to the 100C kinnematic viscosty and make the notation that it would be, say, 4-6 cst at 100C? Using that logic of just looking across the chart would give me the impression that a 10w oil is 4-5 cst at 100C.. which I suppose is true if it is claimed to be a 10w-10, for example.

Just want to be sure that I have it right... Im trying to understand what a VW TL 726-Y fluid is, such as p/n G 055 726 A2. It seems as of right now that if it is a 75W oil, then it is approximately a GL4-rated ATF... something akin to redline D4 ATF, I suppose.

Curious of your take on this.

Thanks,

JMH

 

[Pablo]

The way I think about a pure 75W is meeting the max temp (-40°C) of 150,000 cP and have a min viscosity of 4.1 cSt @ 100°C. That's it.

 

[tom slick]

You were reading the chart correctly.

I love the confusion of the SAE system. why we can't just use ISO is beyond me. then again we can't quite let go of the inch system either.

 

[unDummy]

When an automaker is purposely VAGUE with a fluid spec, ANY that meets it can be used. Problem is that '75w' ONLY fluid isn't easy to come by.

If you truly want to know what fluid you have, all you have to do is VOA the factory stuff. Then you'll learn if it is 75w80, 75w85, or 75w90..... I believe that the VW crowd already UOA/VOA'd this fluid.

~7cst, lifetime fill, minimum transmission wear(gl4), excellent cold weather shifting, seal compatibility.... are the only hints that I will provide. The VW spec also works well in manuals that require ATF.