I haven't had to lower the spare tire yet. However, in reading the owners manual about doing that, I'm confused about the secondary lock mechanism. Would someone please explain that to me -- particularly about how to lower the spare if it won't come down due to the secondary lock system? Also, any preventative maintenance on the secondary lock system -- like greasing, etc. How do you put the spare back in it's place and ensure the secondary lock system is engaged? Thanks Gene