Differential Fluid Change

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Jul 24, 2013 | 01:44 PM

aidandj

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From: Corvallis, OR

Differential Fluid Change

Hey all,

I've been researching changing the fluid on my 72 F100 4x4. For the Ford 9" rear end it seems the recommended method is to pump it out then refill. Do places like Jiffy Lube or Oil Can Henry's do a flush? And is this flush better than what I could do with a pump at home. Also for the front differential do I just take the cover off, drain it, clean it, reseal, and refill?

Thanks ahead of time,

Aidan

Jul 24, 2013 | 01:48 PM

aidandj

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From: Corvallis, OR

Also the owners manual has something like Ford Hydrofluid or something of the sort. What gear oil should I be using in the diffs.

Jul 24, 2013 | 02:01 PM

Freightrain

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From: Ohio

Pretty hard to pump it out. The fill hole is right off the ring gear and I doubt you can get but the smallest of tubing down there to suck out anything. Let alone get all the sludge out of the bottom. The only GOOD way, but the most involved is pull the center section and clean it all up and put it back together.

I wouldn't trust a quick lube place to actually do it either. Unless you stand and watch. No way you can really check it after the fact.

If you don't have a Limited slip, then standard gear lube will suffice. If you have limited slips then you need the additive to put in, or use lube with the additive in it.

Jul 24, 2013 | 02:05 PM

JEFFFAFA

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From: Phoenix, Az.

Quote:

Originally Posted by aidandj

The best way for the rear end would be removing the 3rd member and there/by completely draining all old gear lube. This would reqire a new gasket and the 10 copper washers that go under the nuts which mount that 3rd member. 2nd would be buying a pump at a local parts store and sucking the old fluid out by the fill plug. A "flush" iS a relative term to sound better. Sucking the old fluid out as I mentioned earlier is exactly what most shops would do. Both front and rear took 90 weight gear oil which most stores now carry as 80w-90. If the rear is a traction loc it will require one bottle of friction modifier added to the 80w-90. And you are right about the front axle cover etc. The synthetic gear oils are up for personal opinion. I personally, would not.