What a read ! Finished all 17 pages in one sitting. I am new to TCs and trying to absorb as much as I can. We have a new 2016 camper and I noticed something in the Happijac manual that came with the camper that relates to many posts here about the different rates at which the legs extend and retract. The manual was very clear in stating that the four corners of what has been called the "box" do not carry equal weights. Some corners are heavier than other corners and that alone is the reason the legs move at different rates (speed). I just thought I'd add this to the pile of knowledge here.