I own a 2000 Jeep Cherokee 4.0L V6 AWD. I am getting a strange rattling noise when I am sitting at a stop light and when I drive in reverse. The noise is coming from the back of the vehicle and is very loud. Any ever experienced this or have any ideas on what this could be?

My first suggestion is don't assume it's coming from all the way in the back. Sound travels and reflects weird under cars.

Take a look at the fire cover on the bottom of your catalytic converter. The top and bottom are tack welded together and sometimes one or more of these welds crack over time and the halves sit there and clatter REALLY loud and embarrassing - just liike you describe - at lights and idling or accelerating. Reason you may not hear it at highway speed is the sound is usually swept away by the wind or hidden by passing traffic noise.

Also, check for loose tailpipe fastenters or exhaust clamps. Maybe you lost a nut and the thru-bolt is jumping around in its U-clamp assembly.

Try and spend an hour or so just laying on your back under your vehicle. Relax and study it - have a radio or stereo and cup of Joe for comfort. Just let your eyes wander across the bottom of your vehicle and notice things - you'll probable catch the problem - and you know what - it won't be what you thought it might be I'll bet.

Cheers from NC NASCAR country.

PS: Dealers don;t have welders from my experience - LAME! But you can find an in-house welder at most muffler install shops and some tranny repair shops.