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.


Ford Ranger/Bronco II 7.5-Inch Axle


Ford 7.5 & 8.8 Inch Axle Tag & Door Codes




edit. I think I DO need friction modifier because the charts say my R5 axle is limited slip (L/S). but I would like a link to exactly what gear oil and friction modifier I should buy from autozone or pepboys etc. I'm in New Jersey if that matters. I want mid grade or high grade synthetics if not too costly.


ps do I need to do this for front axle too or only the back since it's a 2 wheel rear drive and not 4x4?


thanks

 

Look on pages 211-213 in your owner manual for the Ford specification numbers of the rear differential lube & friction modifier additive. & the correct quantity of each.
If you don't have a manual, visit the "Tech Info" thread & scroll down to the "Misc" section for a no cost owner manual down load link.
EDIT: You can also down load a "Scheduled Maintenance" call out chart, to see when various things are ready to be changed out, or replaced.

 

The friction modifier is only for clutch-type, & Torsen limited-slip differentials.

 

===================
Ranger/Mazda B2000, 4.0 V6 OHV 12V EFI,
VIN Number: 1FTYR14X5YTA17327




Features:

• Medium Graphite Interior
• Keystone
• Styleside Box - STL Inner/Outer
• 126"/3200MM Wheelbase
• (-)"XL"
• Edison Plant Build
• With Sliding Rear Window
• With Rubber Floor Covering
• With Drivers Power Mirror
• With Passenger Power Convex Mirror
• With 2nd Row Dual Jump Seat
• Super/Super Single/Super Cab 4 Door
• Bodyside Accent Stripe
• Rear Bumper - Steel Step - Painted
• Rear Bumper - Step Body Colour
• With Front Licence Plate Bracket
• With Driver Air Bag
• With Passenger Air Bag
• 6J x 15 Steel Wheel
• P225/70R 15SL S/BLT RBL A-S
• 3.55
• Rear Axle Limited Slip Differential
• With 8.8 Axle
• 4.0 V6 OHV 12V EFI
• 4 Wheel Anti-Lock Braking System
• Electronic AM/FM/Stereo With Clock
• With NAAO Radio Frequency
• Oxford White
• Ford Series
• 5R44E/5R55E - 5 Speed Auto Trans
• Ranger/Mazda B2000

Takes XXXXXX gear lube & XL3 Friction Modifier.

VVVV----I stand corrected by Pawpaw, SORRY! My Owners Manual states 80W90 and XL3 Friction Modifier.

Wrong for me to assume, as my 8.8 Explorer rearend takes 75W140 & XL3.

 

98 Thunderbolt, I believe you've mistyped the rear differential lubricant viscosity range.
The 2000 Ranger owner manual specifies 80W-90 & & 4oz of friction modifier XL-3 be added to the lube for traction lock differentials.
I can't find any 2000 Ranger TSB's that specify a 75W-140 differential lube here Technical Service Bulletins Search Results, but if you have a TSB that supersedes the above, or the owner manual call out, please post a link so we all may be enlightened.
Ford does say here https://www.fcsdchemicalsandlubrican...nsaxle%20Fluid, that they have a 75W-90 Synthetic that may be used on traction lock differentials, that may be a good choice for the OP, seeing as how he lives in NJ & it gets cold up there in winter. It too would get a 4oz dose of the XL-3 friction modifier for his traction lock differential.

 

I use Mobil 75W-90 gear oil in my Ranger's rear diff (with a few ounces of friction modifier for the LS).

I can't remember exactly where I picked up the M1 diff fluid and the Motorcraft-brand friction modifier that I used, but I know you can find them in most parts stores, at least in my area.