My 1987 300SDL makes a clunking noise whenever I come to a stop or get moving again. I can make it clunk while at a stop by holding the brake and tapping the accelerator and it clunks with every tap. When the vehicle is in motion there is no clunking. I replaced the engine mounts last fall and I replaced the rear axels as well (the clunk is definately not the cv's). Any ideas what may be going on?