woodpecker under my jeep?

[Greencuke]

1043645

ive noticed a horrible vibrating sound comming from the muffler region. it occurs when i start it up after its been sitting for a while (overnight, at school ect) and once ive been driving for a while, it does it again when i stop at lights. I wired the tail pipe down to the chasis thinking that might be it, but i think the vibration is comming from further in, and i cant find it. Its driving me nuts! has anyone heard of this, or have any suggestions on what i do next? [addsig]

 

[RayOvac]

1043648

Yeah man I know what your talking about! Its usually the worst when your sitting still huh? My buddy has a 95 YJ like mine but its auto and stock and he had the same prob. What it is is the muffler support arm gets loose and comes down causing your catylytic converter to bang against the top of your T-case support shield. My buddy took a prybar to his and pushed it back up but it came down again so he is gonna have to put something up there to support it or something. Pushing it up was just a temporary fix but I'm sure that you can wire it or weld on a brace or something. Just look underneath the front of the shield on the passenger side and it should be right there. That should be your problem...check it out and let me know what you find.[addsig]

 

[Craig]

1043659

I had a similiar problem with my 93 YJ. I found a bunch of rocks wedged up under the heat shield for the muffler.[addsig]

 

[dingus]

1043660

or your catalytic converter could be crumbling internally... that happened to my friends grand cherokee...[addsig]

 

[Greencuke]

1043663

well.. i cut my heat shield off w/ a pair of tin snips cause id torn it on a rock pretty nasty; how would i chect my cat coverter for that?[addsig]

 

[billgin]

1043686

My 90 YJ seems to have the exact same symptoms as Greencuke describes. On starting, it sounds like the exhaust system is full of marbles. On idle, it comes and goes. If I pry the catalytic converter up, the vibrating sound disappears, but returns when I release the pry. Thing is that I can't find evidence anywhere that the exhaust system is banging against something else. My mechanic says, "Oh, just something loose in the catalytic converter. Common with Jeeps - don't worry about it." Sure sounds worrisome to me though. [addsig]

 

[californiajeepin]

1043703

man how creepy this is, my 95 yj does the exact same thing already described. I just finished a pain in the ass distributor swap the other night and after I got the jeep fired up again I really noticed that rattling sound, couldn't pinpoint it, now I have some ideas. It comes and goes and I've heard cars make sounds a lot worse so I wasn't to worried about it, just annoying really....I figure if I find what that sound is and fix it, I'll just hear another that will bother me worse ya know?[addsig]

 

[birkie48]

1043780

I had the same problem when my ’98 Wrangler was under warranty. My original dealer couldn’t find the source of the noise. It was driving me nuts. After three separate visits, I went to a second dealer who told me it is common on the TJ’s. The noise you hear is the linkage under the 4WD shift lever. He squirt some lube on the linkage and the rattling went away. Strange thing is that sound travels through the frame, and sounded like it was coming from an area under floor between the seats (around the exhaust/converter). Try throwing a couple of shots of WD40 on the linkage and see if it helps. It worked for me.[addsig]