Replacing and removing rear panel
 

Excuse me if I posted this in the wrong section or if its been answered somewhere in the forum somewhere.

I have a question, I'd appreciate ones who know more about this than me if they can pass down some knowledge. I ordered a rear hatch panel for my 2002 Explorer because the old one tore off (at least most of it). As you can see (picture attached) parts of the old panel that tore off is still stuck. Any suggestions on how to get ALL of the old hatch panel off? I am trying to pry it off and it seems to only come off in tiny pieces. When it comes off do I need to remove the old glue residue off, or is this unnecessary? Once I do get it all off is there a certain kind of glue I should use to make the new one stick well? THANK YOU to anyone with insight!

And a closer look, you can see exactly what I'm dealing with. Than there's lines of glue that go horizontal and vertical. Don't know how important it is to remove this old glue or to put new glue on top where the panel is suppose to stick. Biggest problem now is getting the old panel off