Other times luck runs thin, and the dreaded phrase rear main or axle seal surfaces. The seals that keep oil from escaping past a spinning axle or engine crankshaft are of the same circular variety.

The fourth-generation F-body is equipped with GM's 7.5-inch 10-bolt rear axle. It uses a rubber lip-type seal to keep gear lube from slipping past the pinion flange during normal operation.