75W140 Motul Gear Oil
 

Any of you track addicts running 75W140 in your Diff or Tranny?
Winter maintenance time here and considering this upgrade if appropriate for my occasional cruise - lapping toy.

Yes, I use it in the diff because I track a lot. I cooked the 75w90 fluid.

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I'm also using it in my diff right now since it is compatible with OSGiken.

Did you see any noticeable differences in the way the stock diff worked when you switched to the heavier weight oil ?

No, not really.

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I run it but my car is used mostly on track. Local shop put it in, because I think there is no Motul 75-90 around or because they had found it worked a bit better in one of their shop cars. No complaints but doesn't behave any differently. I don't have a diff temp sensor though so no idea if its helping with temps.

I might give the 140w a try. Assuming the data sheet from Motul is correct it's definitely a more "robust" oil. Even though I track its probably overkill for me as temps don't get very hot here and I normally only do a handful of laps before coming in to let things cool down anyway ha

Having said all that the bottle does say COMPETITION on it so.... :burnrubber:

Do you notice any difference with gas mileage? I mistakenly put 75-140 in 1 of my other cars and the drag from the rear diff in the cold was extremely noticeable.

I don't track my mileage that closely. All I know is that I got better mileage with my C8 than I do with my GR86 despite having less than half the power. :cry: