Inquire at the auto parts stores that rent tools if they have a "Chassis Ear". This is a set of six microphones you clip on to various suspect points. Some are wired to a box in the truck, some are wireless. Drive the truck until the noise occurs, then switch between the mics until you find the one with the loudest noise. By moving the mics around, you can narrow down the source.
Tuesday, March 9th, 2010 AT 3:03 PM