'04 Ranger rear end

[Brian Miller_dup1]

I have an '04 Ranger 3.0 with auto transmission. 4.10 non-limited slip rear end. I want to change to a synthetic rear end oil. All the manual says is Motorcraft 80w-90. It doesn't even say GL-5 or GL-4, etc! I do know that it's not synthetic, because in the manual it lists the specs for the FX4, and it says 75w-140 synthetic (Motorcraft, of course).

Should I stick with a synthetic 80w-90, or would I be better off going with a 75w-90 (which is easier to find).

It doesn't get really cold here, and I don't tow anything.

Is there any advantage in one over the other, other than cold weather performance?

I know that similar questions have been asked, but I just wanted some specific info.

Thanks,
Brian

 

[Titanium_Alloy]

75W-90 would be just fine for your application. If you want the recommended 80W-90, Amsoil gear oil 80W-90 will work well.

 

[Jimbo]

You have the Ford 7.5 inch axle, which is similar to the 8.8 inch used with the 4.0 engines. 75W-140 is current factory fill in the 8.8 (used to be conventional 80W-90). These axles are obviously not picky about gear oil, because the identical axle has had different factory fills just depending upon model year. I think the reason the 7.5 might still use the cheaper stuff is that it is intended for light duty service, probably a tow rating of no more than 3000lbs. I see no reason to change out the factory fill on a new truck unless you have submurged it in water.

 

[TallPaul]

How long does it take a new rear end to mate up, that is, how long will it generate excess metals from being new? Suppose it is pretty much through that stage in say 5000 miles. Then a change would get rid of that stuff. Check out the Redline site. I hear their gear oils are excellent. I believe cheaper than off the shelf synthetic gear lube.

 

[Steve S]

SAE testing on the rear ends of semi trucks find an oil change the first 1,000 miles,then go on the recommended service interval will give the best service. I.M.O. the differential beds in pretty quick . use the recommended vicosity with a syn oil of your choice

 

[TallPaul]

quote:

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Originally posted by Steve S:
SAE testing on the rear ends of semi trucks find an oil change the first 1,000 miles,then go on the recommended service interval will give the best service. I.M.O. the differential beds in pretty quick . use the recommended vicosity with a syn oil of your choice

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Good info Steve. Given a semi is pretty heavy duty use, I wonder if maybe 2000 to 3000 for a car would be a safe leeway.

 

[Palma Pete]

Dumb question maybe.
I have a new front wheel drive van - a Pontiac Transport. Is there a separate differntial in there that should have an oil change?

Or is it part of the transmission?