Originally Posted by cosbourn
So after owning my truck for close to 1 year now I have finally lost all patience with dealing with the faint to annoying rattling (sounds like a tin can or something) coming from the underside of the truck at or right below 2100 RPM. Once I pass 2100 or come back down from 2100 it completely goes back to normal sounding. Performance has not been lost and the truck is getting average mpg so idk if it's my cats. Thing is it only happens when the truck is in gear and under load, ie up a hill or getting on the highway or pulling from stoplight etc.
It was present when the truck had the stock muffler on, so i didn't think anything of it, thought it could be the stock muffler with a broke baffle weld or a loose heat shield. I then switched to a FM40 and the sound was still present. After dealing the massive drone a FM40 has I switched to a Aerotrubine 3030xl and it is now worse than ever. I have tightened every accessible heat shield bolt/screw and tightened. My U-Joints look fine (thought it might be them straining under that particular rpm). I even went as far to take my stock manifold heat shields off as I thought they were causing the problem (one had a broke stud and the heat shield would bounce around). But that didn't help the problem at all.
Everything I am reading is saying that it's the muffler but seriously? What's the chances of having 3 different mufflers within a year, all 3 of which with busted muffler welds? I think not...
I had a 96' Ram that I had to get my cat replaced because it would rattle almost identically sounding but only at idle ~650 rpm. My truck now doesn't have this problem at idle. ONLY at 2100 rpm under load and in gear. SO..with all that being said is anyone experiencing the same problem I am? Any suggestions on things to check? Is there anyway to check the cat's externally before taking them to muffler guy and having him charge me $$$ I don't want to spend?
Thanks a bunch for the input guys!
Only thing I can think of is with the catalytic converter because their is something that rattles around inside the converter. Idk if this is your case or not but all I can think of at this second.