2 people reported this problem
Clunking noise in rear suspension when starting or stopping. on Lexus LS400
Clunking noise coming from rear when stopping and starting. The bushings in my rear carrier arms (I think, it's been awhile since I replaced, crawl under car and find the arm that moves around significantly when pressure is applied) were COMPLETELY worn out, the rubber was missing and the metal housings were just flopping around. Use aftermarket bushing ADUS 505 (about $35 each, search online) to rebuilt each arm. Repair isn't too bad if you have decent mechanical skills, don't attempt if you don't.