synthetics for Transfer and demential??

[Badspell68]

97 5.0 AWD XLT 139k miles
I've read that at my mileage it is best to ad synthetics to my Transfer case and differential. Is this true and is this something I can do easily myself. I'd like to do the rear differential and the transfer case...is there only one transfer case and what oil should I use?

 

[steventadams]

There is only 1 transfer case to fill. synthetic oils are almost always better at protecting the engine/tranny/transfer case/differentials/anything that needs to be lubed...

 

[wolfnutts]

i 2nd that synt oil all around if you can aford it , holds up much better especially in the diff an transfer cases , which almost never see regular maint oil only buy full synth if yours is a 1997 model i thk rear axle takes 80- 140 weight an trans is the weight of auto transmission oil called by different names depends on what brand you buy syncro max - etc etc. mobile one amsoil

 

[mechjames]

if you have a limited slip traction lok differential in the rear, you will need friction modifier, u can tell this because on the door sticker there will be a letter in the axle code, if you don't it will be two numbers, not one letter and one number.

 

[IZwack]

Most synthetic gear oils come with the friction modifier additive.

 

[Badspell68]

My Axle code is D4

 

[mechjames]

you have a limited slip with 3.73 gears.

make sure that the oil you get does have the modifier in it, because if you don't, you'll burn out the clutches in the rear diff.

 

[Badspell68]

Is it hard to change these (the rear dif and the tranfer)?

 

[mechjames]

the rear diff is just a bunch of bolts to pull out, then sometimes the cover itself can be hard to get off. you might need a flat punch and a hammer to crack it off.

also for the rear diff you should get a new gasket and use rtv on it.

as for the transfer case, i think its just a drain plug to drain it out, and a fill plug on the top somewhere. i haven't done my transfer case yet.

 

[mechjames]

Most synthetic gear oils come with the friction modifier additive.

i'm planning on changing the rear diff oil soon, as i drove through deep water last week.

so you're saying if I use the royal purple synthetic, Max gear 80w90, i don't need to add friction modifier to it? and it won't burn out my D4 LSD 3.73? cause i'm kinda leary about that, i know it has the hypoid lubricant in it, but it doesn't say anything about friction modifier

 

[IZwack]

You can always just add it, it wont harm the gear oil if you add the friction modifier. It only costs likr $6 or so dollars from the dealer, and probably less from most auto stores.

 

[mechjames]

alright, and it won't hurt it if there is already some in it and theres too much?

 

[IZwack]

Neh... you're cool.

 

[Badspell68]

OK, so Im a bit confused...for my explorer, listed as D4, could some one provide me with the name of the product so that I can go to the parts store and pick-up? Can I use the same stuff in the Diff and the transfer and how much in each?