[rons2018ATSL]

Well, it's happened to me. Not really a surprise, and with all of the posts about it the actual cause was easily found. That same little strap crossing between the two pipes under the back of the transmission. The way it rattled/sounded you would have sworn that it was something going on internal to the muffler, but not the case - one side of that strap was broken at the weld, and that's what it was. Break the strap Off and the rattle is cured.

Since the car still has Plenty of B-to-B warranty remaining I let the dealership diagnose it, and I now have a new exhaust coming - on national back order..

 

[Jake Turner]

Wow, a MIG welder and 3 minutes comes to mind. 😁

 

[rons2018ATSL]

Wow, a MIG welder and 3 minutes comes to mind. 😁

Yup, nothing to it. But.. The service advisor told me, and I quote, "GM doesn't pay us to weld", so there you have it - one new exhaust system, under warranty. I would note that this little strap Under the two pipes apparently replaces the larger round brace on Top of the pipes that this 2019 car does Not have in that same approximate location - and rather than crack/rip out holes in the pipes this strap just fails instead. Call it a no harm, no foul sort of thing. Makes me wonder just what actually causes the strap or brace to break, what forces and because of what "inputs", and what it would take to prevent it from happening, long term. I also wonder what the harm is of just not having anything There for a brace or reinforcement at that location at all. I almost would guess that the strap is really only there to keep the system intact during shipping/freight, before it gets installed under the car..

 

[Lifespeed]

Yup, nothing to it. But.. The service advisor told me, and I quote, "GM doesn't pay us to weld", so there you have it - one new exhaust system, under warranty. I would note that this little strap Under the two pipes apparently replaces the larger round brace on Top of the pipes that this 2019 car does Not have in that same approximate location - and rather than crack/rip out holes in the pipes this strap just fails instead. Call it a no harm, no foul sort of thing. Makes me wonder just what actually causes the strap or brace to break, what forces and because of what "inputs", and what it would take to prevent it from happening, long term. I also wonder what the harm is of just not having anything There for a brace or reinforcement at that location at all. I almost would guess that the strap is really only there to keep the system intact during shipping/freight, before it gets installed under the car..

I share your assessment the strap/rod is for ease of manufacturing and assembly, not for fatigue life operating in the car. I removed my exhaust brace rod prophylactically, before the rod broke off taking a chunk of pipe with it. No warranty, but also no need for a new exhaust.

 

[rons2018ATSL]

Just to update - the new exhaust "pipe" (actually a complete muffler and pipes welded assembly) arrived at the dealership the week before Christmas, and has been installed. Something like 2 months to get the "national backorder" part in. I still can't hardly believe that GM would replace the whole exhaust for this, and that if they were going to Do that they would not have done Something to change the design to prevent it from happening again, but whatever.

And yes, the new system has that same small strap that failed on the Last one, and the dealership did Not remove it during installation. I told the service advisor I'd see him again, in a couple of years.

But actually I won't - I'm sure that this one will fail just like the last one did, but by that time the car will be out of warranty, even the extended CPO warranty, and I won't waste the money to "fix" it by replacing the thing again - just eliminate the strap (and therefore the rattle) and leave it go.

 

[5615mike]

Same thing happened to my 17PL with 32k on the clock. Replaced under warranty. $1800 is a ridiculous figure.