I'll be installing a diff girdle on my girls 03 gt. I was wondering how much friction modifier I need to put in? I'm going to use
mobil 1 75w140 gear oil. Thanks

 

Most synthetic gear lubes (Mobil 1 included) do not require that additional friction modifier be added. Many are marketed as "containing friction modifiers" but technically that is not so, it's just that synthetic oils are "slippery" enough that friction modifier is not needed.[/align][/align]BTW, A lot of people think friction modifier increases friction in the LSD clutch packs. This is also not so, it actually decreases friction. A trick we used to use in the old days (with dino olis)was to reduce the amount of FM added, and thereby increase a clutch based LSDs ability to lockup...[/align]

 

Does your girl car have gears? When I had my gears done, Mike put 75w 90 synthetic and 1 bottle of friction modifier.