Rear Diff Fluid

[Jacob Dryer]

I changed my rear diff fluid about 2 weeks ago, and now from a post above I've just learned that I actually have a limited slip diff.



I put in synthetic blend (vavoline) 80w90 in the rear with no addatives or anything else. What am I supposed to be running? Will what I put in hurt anything?

 

[Todd Z]

It should run 75w140 synthetic and requires the limited slip friction modifier additive.



If you put the additive in you should be ok, But if you tow, race, 4X4 or drive hard you should replace the fluid....



Todd Z

 

[Jacob Dryer]

Is the additive only from ford?

 

[Rodger Tellefson]

Royal Purple MaxGear w/ friction modifier.

 

[Todd Z]

No, you can use the the one Kendall sells , but the dealers is only around $8.00,,,,



Todd Z

 

[Mark G]

Here is a link to the Ford friction modifier. Enjoy the smell. I picked up a bottle at the local Ford dealer one time and every mechanic I saw had a comment on the everlasting smell. :blink: