Rear hatch adjustment
 

My rear hatch sticks and catches a little when I open the top. When the hatch closes its leading edges are not flush with the rest of the body and are asymmetric (upon closing after catching.)- It seems to get sticky and come out adjustment over the winter after the first few actuations. I have had to have it adjusted flush before....Anyone have an idea as to what the issue with my hatch would be? How is the adjustment done? What do I lubricate etc to get this thing back in proper working order?