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GT350 Gear Oil Changeout

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I saw in another thread that a handful of people were recommending a switch to 75w-140 in the rear end. I'm curious if many are still supporting this idea for moderate track use or if it's best to stick with the factory 75w-85?
 

racer47

Still winning after 30+ years
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Since no one else replied yet, I'll throw out my 2 cents.

I'm not a gt350 expert but I think it has a torsen type rear diff. If so and you go thicker, it makes the diff slightly tighter, meaning slightly more torque to inside tire, slightly more like a spool. But this is not a big change. It can also make the rear end run slightly hotter, but again not by much.

FWIW I run 85w140 non syn gear oil in my Eaton trutrac (torsen style diff).

But, if I were you, I'd just run what Ford says to run. There isn't really much if anything to gain.
 

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