The seal design has been changed for enhanced performance on 2016-newer LCF medium duty trucks.  This seal back-services past model LCF trucks as well.  Due to the seal design change, previously Essential installer GM-39114-A will not work.  To install the new seal, GM-39114-C is used with GM-8092 Driver Handle to seat the seal into the hub to the correct designed position.  Unapproved installation methods may not place the seal into the correct position, and may result in less than designed seal life.  GM-39114-C supersedes GM-39114 and GM-39114-A.