Hi there, does the gear-head require "greasing" at any time please? I've been told by a lawnmower repair outlet that since my Homelite line-trimmer doesn't have a provision for greasing the gear-head, they will need to take it apart. This necessitates removing five screws. These screws have never been off and they don't look like they might all cooperate. What can you advise please? Many thanks - Michelle B