when im driving over bumps or dips in rd,the left rear has a very annoying squeak,i know there is allot of stabilizers back there with rubber bushings,im wondering could it be the rear shock mount bushing,if i push on the bumper up/dwn,it squeaks loud.would a good can of silicone spray help if i spray all the bushings,or is this a sign of something getting worn and loose?thanks

Sounds like the outer control arm bushing (that's what I call it, it seems like there are several names). Check out this thread Rear Outer Bushing Joint Replacement

You will find a lot of information if you search for outer control arm bushing.