Muffler Bearing Rattle "lets learn lets share"

Alright so I figured I would do a mini write up of an experience I had with an exhaust shield that lost two bolts. Hopefully this will be as entertaining as informational.

One day I noticed an ever so weird rattle coming from somewhere. It almost sounded like a bad bearing from a pulley assembly. I spent time looking for it and chasing it to no avail becoming flustered at this point in time. As when I hit the gas the rattle would increase (since the exhaust would shake more causing the loose shield rattle louder) so I was thinking for sure the rattle had to be coming from the rotating assembly. As it was late, I grabbed my keys an slammed the drivers door to call it a night and grab a cold one. As the door slammed my ears perked up as I heard a faint rattle. I then went to look under my Tundra poking and shaking every body mounted shield figuring it had to becoming from one of them. All of them were tight, then I noticed the shield on the most forward drivers side cat was loose and had two broken bolts. So I fished around in my container of spare nuts and bolts finding two Identical nuts and bolts from some other vehicles exhaust system, installed and tightened them. Success, no more noise or rattle I was so relieved.

Embarrassed over a few things that I missed, and felt I shouldn't have. I keep it as learning story an say "well I just needed to tighten the lash on the muffler bearing"

...moral of the story is sometimes things seem definitive in a way. "Rattle got louder with RPM , a sign of rotating assembly" but was something completely 98% stationary. So from that day forward I add and suggest to others to add the door slam to eliminate rattles from non-rotating assembly parts.

feel free to share your interesting story or experience with a troubleshoot or diagnostic that seemed to defy logic or the process. Or just a really bizarre vehicle story.

 

I have to empty rocks out of those every so often, they'll rattle pretty good. Took me forever to find it

 

My brother in law had a bad rattle on his 95 Cherokee that 3 shops guaranteed he had a wasted bearing in the bottom end and needed a crate motor. It also got louder with RPM increase. I didn’t really look it over but offered to help him yank the motor and put in a new one. He brought it over and pulled it in my back yard onto a huge concrete pad I had back there and we got to work. Spent most all weekend taking stuff apart and getting the cherry picker in place. Sunday around 2 we were ready to unbolt it from the transmission (97% engine pulled) and I yanked the shield covering the flywheel to remove the bolts and much to my surprise I found 1 flywheel bolt was missing, and 1 was backed out about 3/4 of the way. That sucked, but all in all it was great news so we finished pulling the motor and put it in the shop on the stand and went through it. New oil pump, freeze plugs etc…

 

I remove those cat and muffler covers as I have had the rattle often on other trucks.

 

My muffler bearings suddenly went out as well. It was intermittent and inconsistent, so I knew it wasn't internal. I crawled underneath and listened. Something was definitely loose. I started hitting stuff until I got it to rattle. Diver's side cat off the manifold. I still haven't fixed it. I haven't decided to remove completely or put new bolts in.

 

Another suggestion that works very well, especially if the cat covers are really rusted or the areas where the bolts attach are degraded- use a couple big stainless hose clamps to secure the heat shield- put it around the shield and cat and tighten it well until no more rattles. This has worked for me on multiple vehicles and was a trick a learned from an exhaust mechanic/builder.

 

Class act right there a real 2 percenter!!