What oil for front/back gears?

[wisneski7]

I want to change the oil in the front and back differentials. What is the recommended oil to use? I can't seem to find any info on this. Thanks!

Aaron

 

[team]

per alldata

front 80w-90
back 80w-90 or 75w-140 for traction-lok differential
it says to use additive for both types in rear

 

[joecrna]

Use synthetic and Ford says don't change unless axle is submerged under water.

 

[Joe Dirt]

Front or rear? I changed my rear this fall when I resealed the rear cover...

 

[techieman33]

Use synthetic and Ford says don't change unless axle is submerged under water.

that's a bunch of crap, the oil does need to be changed every 50k miles or so

 

[96eb96]

that's a bunch of crap, the oil does need to be changed every 50k miles or so

I read somewhere that the synthetic 75W-140 is hygroscopic (absorbs water). In that case it definately has to be changed. Ford had lots of rear end issues when they started switching from 80W90.

 

[techieman33]

I read somewhere that the synthetic 75W-140 is hygroscopic (absorbs water). In that case it definately has to be changed. Ford had lots of rear end issues when they started switching from 80W90.

Any fluids should be changed if submerged in water no matter what the mileage, but if it's just on the street changing the fluids at regular intervals is enough

 

[wisneski7]

Well I picked this up about a month ago and there is 127K miles on the clock. I have no idea if the oil has ever been changed. I haven't taken a real close look, but there is some oil leaking from the rear. I thought I would go in there and change out the fluid for a piece of mind, and hopefully fix the leak. It isn't dripping, but its enough to cover everything around the area. Is it straight up 80W-90or is it a synthetic blend?

Thanks
Aaron

 

[techieman33]

do you have a limited slip diff? look on the sticker on your drivers door, it will say axle code, if it has a D in it you have one, if it doesn't you don't. If it does it needs 75-140, or you could use 75-110. It might also need a friction modifier added to it, you will have to check with the manufacturer of the fluid to see if it needs it or not as some do and some don't. And whatever you get go full synthetic.

 

[fixxxer]

Wisneski7, all that information is in your owner's manual. If you did not get an owner's guide when you bought your truck, there is a link in my signature where you can download an electronic copy of it.

 

[wisneski7]

Thanks for the info/help everyone!

Aaron

 

[Cobraguy]

If it's limited slip, get the friction modifier. Seriously. I don't care if the lube you use says you need it or not. I've fought too many chatters and complaints because the Ford modifier wasn't used and the lube said it wasn't necessary. Royal Purple maybe?? It's about $5. Just use it and be done with it and you won't have any problems.

 

[techieman33]

If it's limited slip, get the friction modifier. Seriously. I don't care if the lube you use says you need it or not. I've fought too many chatters and complaints because the Ford modifier wasn't used and the lube said it wasn't necessary. Royal Purple maybe?? It's about $5. Just use it and be done with it and you won't have any problems.

I haven't had any problems with my amsoil fluid

 

[X-Files]

even my owner's manual said use 80W-90 in Front and Rear, I still want try some new stuff .

so I use LUCAS 75W-90 in front ,Royal Purple 75W-140 in rear ( its not limited slip, so not fill the friction modifier )...everything is fine , especially in Cold weather.