Abstract: A shock absorbing subassembly with a body, a mandrel slidably and non-rotatively received in the body, dampening means therebetween, an upper seal above the dampening means and a floating seal therebelow for maintaining an oil bath between the body and the mandrel, a primary seal between the body and the mandrel below the floating seal, and a secondary seal actuated upon a predetermined magnitude of leakage past the primary seal to sequentially establish another seal between the body and the mandrel above the primary seal and below the floating seal.