# Fluid change day. What kind of rear end gear oil and posi fluid?



## shep28 (Jan 1, 2010)

It was nice to see that there were no metal shavings on my magnet and the gears look like new. I have seen conflicting info. on the type of gear oil that I should purchase.
75w90 or 75w140 rear or 80w90

How much of the posi additive do I add? I have 4.10 rear. Limited Slip


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## jhenderson9196 (Nov 14, 2010)

What year truck? 03 and newer:75-90 synthetic, no friction modifier needed. 02 and older: any good gear oil plus friction modifier. A Dana rear will run almost anything.


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## Chiputz (Dec 28, 2010)

get 2 qts of gear lube and put the whole small bottle of friction modifier in. You'll end up a little gear lube unused because of the posi additive.


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## jhenderson9196 (Nov 14, 2010)

2003 and up trucks use AAM axles. They have gear type posi units and DO NOT use any additives.


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## tastebeer (Dec 10, 2008)

jhenderson is on the mark, I do think the axles are supplied by American Axle from 03 and newer. Dodge may have gone back to Dana in more recent years.


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## jhenderson9196 (Nov 14, 2010)

No, they have not


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## NBI Lawn (Oct 15, 2007)

Jhenserson is correct, no modifier needed on the 3/4-1tons. I put AMA il in my truck and the rearend chattered really bad. I though the rear end was goin out. Ran it like that for about 10,000miles and the witches to mobile 1. Problem went away instantly.


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