[MrClean]

It says that somewhere in the instructions or online somewhere. If the washer isn't cleaned and greased it can catch and give you a false reading on the torque wrench. Also, the slightest hint of dust sometimes can keep a pulley from sliding all the way onto a shaft. Just a little rap with the wooden handle of a hammer can seat it. Been there, done that, except it was on the primary input gear of a Toro reel mower unit. That also happens to be the first place I ever used an impact screwdriver.