Which type of Permatex RTV is appropriate for differential seals? I know the red is the high-temp stuff rated for 650 degrees F. The differential will NEVER get that hot (and if it does, the gasket is going to be the least of my worries). Will the blue RTV be appropriate (rated for 500 degrees F)?

 

i would recommend black rtv.

 

Ah, got it. The black is rated for 500 degrees F, but provides max oil resistance.

 

Buy a gasket.

 

Went w/o the gasket, and only used the black rtv about a year ago. noticed last week it's starting to leak. I know there wasn't a gasket installed at the factory, but autoparts stores carry them. I contemplating the gasket, or buying the sealer from Ford. Never had a problem when I used the Ford sealant.