right rear thump when i hit ANY bump in the road nothing seems to be loose, in cabin , trunk or wheels.

my brother thinks its spring shocks?

 

Could be shocks(struts). I have a thump or clunk from the right rear and have pinpointed the source to be from the right rear strut. Although I did check everything else on the suspension first. Are the rear struts leaking oil?

 

See if your spare tire may be lose.

 

i did that. nope

 

i tired to jack up rear end to take a look, only to find factory jack isn't very suitable. i couldn't find a rear site to put sizzor jack . it has a slot to grasp a pinch point. works fine on front end. every thing online say jack up at differential but sizzor jack seems ill suited for that.

 

A scissor jack is ill suited for anything other than dropping a car on yourself

 

DO NOT use the scissor jack on the differential. Use a floor jack under the center of the housing ... shown at the end of below video

You Tube

 

Check the top nut on the rear strut, as well as the three mounting nuts that surround it. This will essentially require removing the rear seat and peering under the cargo shelf. There are directions for this on this forum.

If that top nut gets loose (possibly from shrinkage or compression of the rubber bushing), you'll get a knock or thump when going over bumps. This happened on my car.

 

A thump in the rear over bumps is most likely either a failed strut and/or strut mount. Could also be failed rear control arm bushings but this is unlikely. Both of my LS's had this issue and both times it was blown-out struts. Look for any oil residue on the strut body.