90 vs 140 gear oil?

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bigbendjon

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is there any reason why 140 gear oil should'nt be used in "85 C10 differential can't be used?
 

Bextreme04

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is there any reason why 140 gear oil should'nt be used in "85 C10 differential can't be used?
Other than there being absolutely NO REASON to do so? '85 C10 should be a 10 bolt rear. It's basically identical to the 10 bolt used all the way up into the 2010's. My 2011 K1500 Suburban calls for 75-90 synthetic and I usually use this: https://www.walmart.com/ip/Valvolin...qYB4uqJ2uRonQuNSDbUn7rxamLZul6jBoCtjkQAvD_BwE

I've got 230k miles on it of my wife daily driving it and using it for family trips and hauling our 6500lb travel trailer all over the place. No issues. It is still using the original formed rubber gasket and has been reused at least 5 times and still has zero leaks.
 

bigbendjon

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I have about 3 gals of 140 that I don't want to dump.
 

Ricko1966

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Give it,sell it, to someone that needs it or save it for when you need it. The thicker gear lube is used in slower moving applications,I'm afraid you will starve the bearings before the gear oil ever gets warm enough to flow properly.
 

bucket

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There's a lot of newer trucks that call for the 140 oil. I'd be inclined to use it if I had it, especially in a high load application. But that's not a professional opinion, just my opinion as an occasional thrifty cheap ass.
 

Octane

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I'd use 140 in the warmer months.
 

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