Sliding Rear Window Rattle

Hello all, I have a very obnoxious rattle coming from the rear of my cab and I can only assume its the sliding rear window. There is a little bit of play in it so I'm guessing that when I'm driving off road (which I do everyday for work) it moves around quite a bit. Also I have two 10s mounted behind the rear passenger side seat that make the window rattle as well. Does anyone have a suggestion to stop the rattle? I was going to use some window moulding or weatherstripping but wasn't too sure of the best location to put it. Thanks

 

anyone?

 

i have that same problem with dual 13.5" jl audio subs behind my seats im going to do mad research today I nned it gone today.