My mechanic replaced the cat. conv. on my '03 Disco and it creates a loud exhaust sound 35-45 mph. How can it be corrected? Thanks, Mark. I'm new at this forum so I'm kinda slow.

 

He (they?) probably replaced it with an aftermarket system that's not nearly as soundproof as your original and you're hearing a byproduct of that. Unless you want to for over a couple thou for an LR version then you might as well get used to it. Beyond that, inspect for leaks.

 

Test for leaks first, I second that. Attach a compressor to the exhaust (find a plastic bottle that fits into the pipe and attach a Schrader valve or quick connect to it) and spray soapy water on all exhaust connections (when the system is cold of course).