Install engine retarder assemblies.
Clean mating surfaces of retarder housings and rocker lever housings.
Turn retarder housings upside down.
Apply petrolatum to outer area of oil seals.
Insert seals (flat surface down) into hole located in center of web of each housing.
Place new gaskets on rocker arm housings.
Carefully place retarder housings on studs and seat in position.