80W90 rear diff fluid ok for 8.25?

[shadango]

I want to run conventional diff fluid (not synthetic as I am worried about causing leaks)....

Looking at Lucas Oil 80W90.

This is an open diff.

Sound ok?

 

[BudW]

The 8¼ holds 4.4 pints of GL-5 lube.
If temperatuire.is above -10’ F use 90w, 80w-90 or 85w-90
If as low as -30’ F use 80w, 80w90
If below –30’ F use 75w

Fluid level should be just below the rubber fill cap, when checked on level surface.


FYI: The weaker 7¼, holds 2.1 pints.
I’m guessing you have an 8¼” differential (but your post above didn’t say).

 

[Aspen500]

Not sure if the synthetic would cause a leak. Have synthetic in the Aspen and my '96 Dakota got switched about 15 years ago (made a HUGE difference in winter). Of course the Aspen has new seals, yoke, bearings, axles, etc.... but the Dakota has never been apart (155,000 miles) and doesn't even seep.
Your results may vary though.

 

[Master M]

I want to run conventional diff fluid (not synthetic as I am worried about causing leaks)....

Looking at Lucas Oil 80W90.

This is an open diff.

Sound ok?

Sounds good to me. I always avoid synthetic lubricants on old seals.

 

[shadango]

Thanks guys. Got the lucas oil. And yes it's an 8.25 open different rear.

Not removing the cover this time, just gonna use our sucker and drain it that way.