new uca installed now it makes a bump or knock sound

I just installed the J&M upper control are ( the soild one ) and now everytime I run over a sharp bump in the road I hear and feel a bump or knock, like the rear end comes up fast and hard and hits..

I really don't think it's then driveshaft making that knock sound... It kinda feels like the rearend is bottoming out...I can put my hand under the rear seat and I can feel something hitting. I thought maybe the upper control arm bracket wasn't tight under the back seat so I took a breaker bar to it and I thought I was gonna break that bolt. Maybe something isn't lined up right under there. I had the dealer look at it and they said everything looks fine..

UPDATED:

I figured it out! I'm a idiot...lol... I had the upper control arm mounted upside down. one side is somewhat boxed and the other side is open.. the boxed side was really close to the rearend and the rearend would smack the arm sometimes over sharp bumps... Works like a champ now!