grinnellbrent

I recently purchased a 02 2500 hd with the 6.0. Love the truck, but have a few noises I can't figure out. First; there is an exhaust leak somewhere between the exhaust manifold and the cat. I have replaced the flange gasket between the actual exhaust pipe and the drop down from the manifold...still leaking. It only does it for the first 10 miles or so after start up and then quits. Second; while backing up slowly there is a low pitch intermitent squeak coming from around the rear axle or drive shaft. Not going foward, but only in reverse. It looks like it has a new u-joint on the rear drive shaft, but not sure. One more; there is a light rattle under the drivers side dash, I'm sure it's nothing mechanical but just extremely annoying. Any help advice on any of these would be much appriciated. THANKS!!!