The left and right CT6 Front Drive Unit (FDU) output seals are installed to a specific dimension, and this dimension differs between the left and right sides. GM-51976 is a double-ended installer that installs both seals to the correct, engineering-specified positions. Once the seal has been removed and the case cleaned, the GM-8092 driver handle is installed onto the GM-51976, and the seal is placed on the other end of the GM-51976. The seal is then installed using a mallet against GM-8092. Failure to use GM-51976 may result in incorrect placement of the seal and a seal life shorter than designed.