Quote Originally Posted by JoshS View Post
I think of the diff as part of the drivetrain; it's in the same category as the engine and transmission...
Ergo:

- Since motor mounts are part of the drivetrain, and suspend the engine, they're free;

- Since rods are part of the drivetrain, and suspend the piston, they're free;

- And since the head is part of the drivetrain, and suspends the cams, it's free (and the cams suspend the rocker arms, so they're free too...)