96 ram, 2WD v6 auto. Theres a horrible rattle, sounds like sheet metal, that appears to be coming fron under the truck either near the passenger seat or just behind it. really bad at or around 1500 rpm, which happens to be most of the time. its also very noticeable at idle. ive had it in to the exhaust shop twice, mechanic twice, and the transmission shop once. no one knows what it is. cat seems silent when tapped. i have one broken exhaust clamp, but its on the tip, nowhere near the sound. had the transmission serviced, belts adjusted. recent tune up done. the shop had removed and remounted a few things underneath, like the starter bracket i think. noise got a little worse after that, but cant make the noise ourselves.

throw out some ideas, ill check them all at this point.

 

have u checked your muffler or exh. system for holes, i know you said you have the broken clamp but i heard mine and was expecting just a hole in my pipes but it was my muffler had developed a hole and when im cruising along i can here it vibrating under the bed the hole was right next to the inlet granted this is some knock off aftermarket job the previous owner put on but this just makes it easier for me to go ahead and slap another flowmaster 40 series under there and dump it lol

 

I had a rattle caused by the heat shield on the cat.

 

Do a search. There is already another thread where guys were complaining about the same thing. Maybe you can get some ideas from that.

 

entire exhaust system is in great shape. no holes anywhere. and i also spent about 20min searching before posting, nothing seemed to match.

someone once thought about it being the cover for the torque converter, but thats already been checked as well.

 

My money would be the cat heat shield or the exhaust heat shields that are connected to the truck. The heat shield on the top of the cat is very common. I'd ask the exhaust guy to spot weld it whether he thinks its it or not.

 

+1 on the cats,,, first my was the heat shield i fixed that and a little time atfer the noise is now in side and its bad,,,,,, try a rubber hammer and tap around the cat or pipe and see if you can track it down

 

Here's a TSB on the cat, this may be the issue you are hearing.

http://dodgeram.info/tsb/2005/11-006-05.htm

-D