Have a 2007 1500 Hemi,don't know if the front diff oil ever been changed bought used w/ 13k now has 49k thought I'd change the fluid, does the cover need a gasket or or just permatex. Thanks

 

Clean up the mating surfaces really good and use a high temp RTV silicone. Usually it comes in the red tube (also takes 24h to dry before you can add fluid, so run your errands first). Permatex should work, too. Just verify the temperature rating is at least 250F.