2018 Traverse Noise Symptom Help

[doitmyself]

My adult daughter's well-maintained 2018 Traverse with 65,000 miles makes a "metallic rattling" noise during slightly heavy acceleration and deceleration at moderate speeds. No codes. An independent mechanic could not find the issue. No apparent loose heat shields or anything underneath. A search on Traverse forums shows a few others with the same problem, but no solutions.

Anyone have ideas? Diagnostic procedures? Timing belt?? Muffler or cat converter internal loose parts? Thank you very much.

 

[oldcodger]

Have you tapped on the catalytic converter? Maybe something is coming loose inside.

 

[Egg_Head]

I would drain the ATF (very easy, 5 qts.) pour through a rag and look for any debris. I went through 2 torque converters in my former Acadia.

 

[OneLonelyBurrito]

Is it AWD? If so, it might be worth check out if its the viscous coupler for the AWD system.

 

[JTK]

I haven't come across this one and have been following 2018+ stuff pretty heavily since buying our 2021 about 6 weeks ago.

Exhaust system issues are pretty common on 2018-2020. The elbow leading to the rear bank catalytic converter can crack. Plus exhaust breaks near the flex joints is common.

Does the noise seem to be coming from under the hood, or elsewhere?

I wonder if the shop she took it to was able to run it in gear while up on a lift.

As @Egg_Head said, it is very important to do drain/fills on this 9T65 transmission if she hasn't. Super easy to do. All the driveline fluids are easy DIY.

 

[doitmyself]

I haven't come across this one and have been following 2018+ stuff pretty heavily since buying our 2021 about 6 weeks ago.

Exhaust system issues are pretty common on 2018-2020. The elbow leading to the rear bank catalytic converter can crack. Plus exhaust breaks near the flex joints is common.

Does the noise seem to be coming from under the hood, or elsewhere?

I wonder if the shop she took it to was able to run it in gear while up on a lift.

As @Egg_Head said, it is very important to do drain/fills on this 9T65 transmission if she hasn't. Super easy to do. All the driveline fluids are easy DIY.

You nailed it, thank you. The dealer found a broken exhaust bracket upon second inspection. About $700 to replace the assembly or $150 to weld it back together.

For others - there is a TSB and free repairs for 2019 and up models. My daughter's 2018 is not covered for the same exact failure. She's quite the bulldog and sparred as best possible with the dealer management. Any advice to get them to cover this?

https://static.nhtsa.gov/odi/tsbs/2022/MC-10209241-0001.pdf

https://gmauthority.com/blog/2023/06/gm-to-fix-2021-chevy-traverse-front-exhaust-pipe-issue/

 

[Egg_Head]

GM standing behind it's products again.