differential lube??

[navyeoseabee]

hello, i just did a rear inner axle seal on my 2007 f250 4x4. it has a limited slip diff. my question is:

should i use the $75.00 worth of OEM synthetic 75w/140 (mobile brand) that i already bought? with the friction modifier?

has anyone used this stuff? (friction modifier)

i am kinda nervous...i want the thing to last. but kinda old school...90w/80w type. and really what is the friction modifier?

new-school seems to be $$$$!


also -i could have bought 5gallons of 90wt....with the $75.00 for 5 quarts of 75-140 syn.





i will be pouring this in tomarrow am, i need to drain the diff first.

thanks for any posts/ help here.

[Evil Eye]

You MUST use the 75w140 and the friction modifier. BTW, I don't believe I have used all 5 quarts when servicing both differentials. Pretty sure it was just shy of 3 quarts on the back on 2 quarts in the front, but it has been a couple of years. I get to enjoy that fun here again in 9k miles...

[PolarBear]

Yes definitely use the 75-140. The Amsoil website says the Dana 80 rear axle with the Limited-Slip takes 8.5 pints or 4.25 qts.

[navyeoseabee]

last i found the steel tags on the bolts holding the rear diff cover on that state 75w-140 so i'm sold...


i have the sterling 10.5 rear end,


i think this link will help people flushing their rear axle.

http://www.guzzle7pt3.com/rdiff.php