Gear Oil Question

[profdlp]

My manual says the rear diff should get 75W-90 (Synthetic) for normal use and 75W-140 when towing. I don't tow all that often but it is not that rare of an occurrence either.

Getting ready to change it and not sure what to buy.

 

[lfhoward]

I think I would go with the higher weight oil if the thing you’re towing is more than 2000 lbs and you tow a few times a year. Probably the difference is a fraction of a mpg overall.

 

[LibertyTC]

I use Lucas 40% synthetic (75w-90) - & 60% 85w-140 Dino.

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After 24 hours in freezer, it pours nicely in cold conditions too!

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[LibertyTC]

* Oh & since I have a Trac-Loc rear diff, I have to add a 10 oz bottle of Mopar limited slip additive- Part # MS-10111

 

[profdlp]

What kind of a fanatic freezes their stinkin' gear oil?!!!!!

Actually - that is a brilliant idea, and I bet you feel better in the winter knowing the stuff is not sitting in there like pine sap.

As for the gas mileage, I quit thinking about that years ago. Anything I do now is with an eye toward longevity, not efficiency.

I may just go for the TC Cocktail™ this time around.

 

[LibertyTC]

If it makes it any easier Prof, the 50/50 mix works great as well.
You can be assured the Lucas Syn & Lucas Dino mix will protect the rear diff in all temperature conditions.
I service the rear diff every 35 k miles, by dropping the cover & inspect for wear, particulate matter.
The Lucas TC cocktail was still relatively clean!

 

[Johnny O]

I use the heaviest suggested weights in mine. No issues in winter and piece of mind in summer. Nebraska gets the extremes in both seasons and my daily drive is less than two miles...and you know what my work/hobby drives are like.

Last gear oil change after 2 years of what I do was unneeded, but did it anyway.