"If your differential requires service at the pinion, this component may need replacement. The PORC Off Road Products rear pinion oil seal is designed as a direct replacement for Jeep models equipped with AMC 20 rear differentials. This seal installs at the pinion yoke and is constructed to match factory fitment and function. Designed for applications without a pinion nut included, it provides consistent fitment and function. Manufactured with a metal outer shell and rubber sealing surface. Replaces OE reference 3208474 and interchange part number 16521.07."