Friction modifier additive in a non slip diff?

[andypinto]

Hello everyone:

I have the (in) famous whine sound (annoying but not so bad) in the rear pumpkin of my Explorer 2002 XLT 4X4 4.0 L.
I read somewhere (I didn't recall where) that adding the friction modifier additive intended for the limited slip differentials to a non limited slip differential (my truck has a 3.55 non limited slip) helps to decrease this whine sound.
Is that true ?
Any help or advice will be greately appreciated.

Thanks and happy rides.

Andy

 

[94 Crawler]

Friction modifyer is designed to reduce the chatter between the clutches in a limited slip diff. such as the Ford traction lock. Altho friction modifyer has been used in several places it was not designed as a home remedy I doubt if it will give you the desired results. A wine in the rear diff is caused by incorect meshing of the ring gear and pinion (or worn gear set). The reason could be incorect tolerences, wear, or even worn pinion bearings (which should also have a grinding sound). If its been rebuilt because of worn bearings the gears may have reset a new contact patch which could also cause this problem after rebuild. Either way any thing that you pour into the diff is little more than a bandaid. Good luck

 

[andypinto]

Thanks for the advice, Michael.

Happy Holidays

 

[gijoecam]

Indeed, if a diff is making noise, there is no remedy except to open it up and see what's wrong. No amount of additive of any type will fix a bad differential.