RATTLE COMING FROM REAR OF VAN

Could be swaybar bushings or exhaust heatshields rattling. If it's swaybar bushings, you need to replace them. If it's the exhaust heatshields, there could be a pebble lodged in it or maybe simply putting a bend in the offending shield would stop the noise. That's all assuming that you don't find something obvious when you try to ID the noise.