Orange Funtastic N64 Controller Squeaks

Hey guys. A while back, i put a new stick into my orange n64 controller. Recently, i've realized that the two halves of the shell seem to move around a bit, and even squeak when squeezed a bit. I'm incredibly OCD about my games, and its been bothering me a ton. I don't remember if it had been like this before I messed with it, or if this is common, but i just want to know how/if i can fix this. I don't want to tighten the screws too much, but i tried making them as tight as i could without forcing too much. No luck, but one of the handles on the controller seems to be fine now... any ideas? Thanks!

 

A little update, I have opened two other controllers in the past, 1 standard black controller and one purple Funtastic controller. Both those controllers feel tight and fine, which leads me to believe this controller may have been like this before hand and I just never noticed. Still the question stands, is there any way to go about fixing this?

 

The two halves of the casing are rubbing and squeaking?