Which differential oil? Friction Modifier? 2000 Ranger R5 axle

[rogerranger2122]

Here's a picture of my door tag if that helps. I REALLY don't want to mess this up. The Differential doesn't have leaks or problems that I know of. I just think it's time to change it.

It's a 2000 Ranger 2-wheel drive (rear) 4.0 Liter 6 cylinder with 70,000 miles.

There's no Tag on the differential bolt, it's missing. Written on the actual differential housing is rf-f07w-88.


Maybe someone knows from this chart below which oil I should use and if I need Friction Modifier? I read it's imperative to use modifier if needed but also imperative to not use it if not needed.

http://www.therangerstation.com/tech_library/Ford-7_5-axle.shtml

http://www.therangerstation.com/tech_library/axle_codes.shtml

I'm pretty sure I do need Friction Modifier because the charts say the R5 axle is Limited Slip (L/S), but I would like to know a link to exactly what gear oil and friction modifiers I should buy from autozone or pepboys etc. I'm in New Jersey if that matters. I want mid or high grade synthetic oils if not too costly. thanks

p.s do I have a front axle I should do this to also? Or no because it's only rear wheel drive and not 4x4?

 

[adsm08]

Oil weight should be 75W-140. If it is limited slip it needs friction modifier. If it isn't limited slip putting it in won't hurt anything but your nose (the stuff stinks, it is the only smell that can make me wife gag).

I would just buy the Valvoline 75W-140 full synthetic. It already has the friction modifier in it.

This stuff:
http://shop.advanceautoparts.com/p/...il-1-quart-vv982/7070058-P?searchTerm=75w-140

Since I am a big fan of teaching people to think and do for themselves I will not tell you if you have a front axle (you have actually answered that question in your post). Go look at the truck and see if you can figure it out for yourself.