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Correct me if I'm wrong, but a synthetic like Royal Purple does not need the friction modifier, because RP already has this stuff in it.
Depends on how sensitive your rear axle is,you still have to add XL3 sometimes to them.
Originally Posted by kaboom10
You're wasting your money when using the premium synthetics. They have the friction modifiers in them already. I use Amsoil brand in mine.
You still have to add it sometimes, 2 out of 5 will need the XL3 added to them any way.
Originally Posted by FordCountry
I went to the dealership to get the fluid and gasket, they said ford does not offer a gasket for the rear diff. what gives? I found one at o'reilly's but the FORD DEALERSHIP doesn't carry one?
Motorcraft part #TA-30
The best thing to use on it.
Originally Posted by kaboom10
The factory uses silicone as a gasket. The place that did my rear end used it to and it works fine.
Why mess with a gasket slipping if you don't need too?
Correct me if I'm wrong, but a synthetic like Royal Purple does not need the friction modifier, because RP already has this stuff in it.
^^^^ This is correct I have built and serviced many differentials and had 0 failers with Royal Purple and any additional friction modifier is just a waste of money
05-25-2010, 04:44 PM
