The pipe between the cat and muffler on my '01 rusted completely off at the flange, so I fixed that. Before I looked to see where the leak was, I thought the muffler had a hole. I was relieved to see it was the pipe which was both cheaper and easier to fix. Once I got the pipe repaired, I looked under the truck while it was running and saw exhaust vapors coming from the sides of the muffler, so it needs replaced too - but not right away! Replaced the original serpentine belt on my '02. It was time after 15-16 years and 89,000 miles. It felt pretty dried out. Also greased the caliper pins on the front brakes, which I didn't do for some reason when I did the brakes 3-4 years ago. I won't make that mistake again! Since I had the front tires off, I rotated the tires, front to back.