Diff Fluid...

[2007_Crown_Vic]

Hi, I was searching some posts here and there seems to be mixed opinions about diff fluid types and friction modifier. It seems a lot of people say synthetic fluid doesn't, or at least shouldn't need friction modifier. They say to run it and if there is chatter add a bit.

I was planning to use Pennzoil Full Synthetic. Anyone else used this? How did it work for you? Thanks!

 

[Mustang5L5]

I've run the Mobil 1 limited slip diff oil in my car for almost 20 years now. Been changed a few times. No chatter, no issues and my car still 2-wheel peels with the orginal, never rebuilt clutches.

I've never added additional friction modifier.

 

[2007_Crown_Vic]

I've run the Mobil 1 limited slip diff oil in my car for almost 20 years now. Been changed a few times. No chatter, no issues and my car still 2-wheel peels with the orginal, never rebuilt clutches.

I've never added additional friction modifier.

Thanks. On Pennzoils website they say this has sufficient friction modifier already in it for most applications, and that only newer high horsepower cars may need more. I guess I will use it and just see if it chatters at all. Being a bone stock 1990 GT I think it should be fine...

 

[Mustang5L5]

In the past, folks have always said to try it as is, and then add friction modifier if needed. I think i've done 3 drail/refills with the Mobil and never needed to add it.

 

[AeroCoupe]

I use the Mobil 1 and modifier but I have the F150 “Z” spring so it puts a bit more pressure on the clutches and the modifier was recommended by others that have this setup.

Run it without as it’s easy to add.

 

[WhiteCobra95]

Royal purple also says that friction modifier isn't necessary. I got that reply from their tech support when I emailed them about twelve years ago.