My 03 toyota highlander/4wd do make Loud sound when I am driving reverse' the sound most time comes from the right back leg'. Though my friends suspected the shock absorber' guys, pls any clue on what could be wrong? Should it be the shock absorber, how much does it cost to fix up... I will appreciate prompt response.

your description of the problem is not lucid enough, then what kind of sound, growling?squeaking?grinding?whistling? are you sure it is only when you are reversing? are you reversing on a very rough road? if what you mean by right leg is the right wheel, then it could be brake pads or hub, be sure to also check the stabilizer linkages and bushings, and all other bushings in the rear.