2021Yukon/ Intermittent rattle under truck at low speeds

[paspasero]

Good news everyone! I found the source of the rattling/squeaking and exhaust smell in my vehicle. I put my Yukon on my lift and started shaking and banging at the exhaust pipes. Ultimately I heard the rattling noise which was coming from the flange where the driver side exhaust manifold meets the cat converter down pipe. I believe the service department that did my lifter replacement failed to put in a new exhaust gasket or over torqued the nuts (two were stripped). This condition allowed the exhaust pipe to wiggle within the flange. I set my phone to take video and did a cold start. Lo and behold, I got smoke! Here’s the video:

I took it to a different dealer and showed them the video. No questions asked, they took my SUV, fixed it, and was ready for pick up the next day.

Hope this helps those experiencing similar issues.

Thanks again for your input everyone!

 

[bradac]

that’s exactly the issue I’m having I suspected it was that same area. As I crawled under annd had the same nose. I have bad neck issues though I’m not sure I’m gonna be anboe to replace that exhaust donut myself. Are you out of warranty ?

 

[paspasero]

that’s exactly the issue I’m having I suspected it was that same area. As I crawled under annd had the same nose. I have bad neck issues though I’m not sure I’m gonna be anboe to replace that exhaust donut myself. Are you out of warranty ?

Not out of warranty yet so I had my local dealer take care of it. I did however buy the replacement rings/gaskets just in case I need them after my warranty expires.