Duramax rattle/vibration when accelerating, sounds like it's coming from exterior

[chrisbusnut]

I've got a vibration that's associated with the engine that I only hear when accelerating at low speeds and certain low engine RPMs. It sounds like it's coming from the right side of the vehicle, either underneath or at the back of the engine compartment. Today I also started to hear it under acceleration at higher speeds and RPMs. There was another post where someone stated that they found some issue relating to the mounting of the power retractable running boards (if I remember correctly), however I am unable to find it. The sound is like metal on metal to me.

The Duramax is a lot noisier in general than I expected it to be, coming from a 6.2, to the point that I went and drove another brand new Yukon Duramax at the dealer to compare. I've pretty much come to accept that it's just a smaller engine, and of course is a diesel, hence the lack of audible refinement that I am used to with a gas V8 (that's solely my opinion, obviously). I have a 6.6 liter Duramax in my Sierra HD, and that sounds completely different. But that's a much larger engine, and it definitely has the diesel sound.

I can accept the inherent sounds of the 3.0 Duramax, but there shouldn't be any rattles/vibrations. I've already had the dealer check heat shields and the exhaust system, and of course they didn't find any issues, however if someone else has experienced this noise and has successfully diagnosed and fixed it, I'd love to know how they did it.

Thanks in advance.

 

[LordWayback]

If it’s only low speed or idle it could be a motor mount that’s on its way out

 

[chrisbusnut]

If it’s only low speed or idle it could be a motor mount that’s on its way out

Well, it only has 1,500 miles on it, so I hope that's not the case. I probably should have clarified that. 2024 Yukon Denali w/1,500 miles.

 

[StephenPT]

https://www.tahoeyukonforum.com/threads/another-warranty-issue-with-the-wifes-21.144360/post-1823600

Worth a closer look - sounds like a similar issue, maybe?

 

[LordWayback]

Well, it only has 1,500 miles on it, so I hope that's not the case. I probably should have clarified that. 2024 Yukon Denali w/1,500 miles.

Wouldn’t know the answer then stuff that new I have no knowledge on

 

[Stbentoak]

This is about the most "Un-Dieselly" quietest diesel I've owned, and I've owned plenty. I've had many guests ride in ours and they are SHOCKED it is a diesel and said they would have never suspected that, otherwise....

 

[Canadiansteelman]

I've got a vibration that's associated with the engine that I only hear when accelerating at low speeds and certain low engine RPMs. It sounds like it's coming from the right side of the vehicle, either underneath or at the back of the engine compartment. Today I also started to hear it under acceleration at higher speeds and RPMs. There was another post where someone stated that they found some issue relating to the mounting of the power retractable running boards (if I remember correctly), however I am unable to find it. The sound is like metal on metal to me.

The Duramax is a lot noisier in general than I expected it to be, coming from a 6.2, to the point that I went and drove another brand new Yukon Duramax at the dealer to compare. I've pretty much come to accept that it's just a smaller engine, and of course is a diesel, hence the lack of audible refinement that I am used to with a gas V8 (that's solely my opinion, obviously). I have a 6.6 liter Duramax in my Sierra HD, and that sounds completely different. But that's a much larger engine, and it definitely has the diesel sound.

I can accept the inherent sounds of the 3.0 Duramax, but there shouldn't be any rattles/vibrations. I've already had the dealer check heat shields and the exhaust system, and of course they didn't find any issues, however if someone else has experienced this noise and has successfully diagnosed and fixed it, I'd love to know how they did it.

Thanks in advance.

I have a 2023 GMC Yukon Ulimate Denali diesel. I love the Duramax engine. Would take it over a 6.2 gas any day.
I also have noticed a rattle or rumble coming from the backside of the engine, possibly exhaust system when the engine is running around 1500 rpm and is put under load. For example, starting to climb a hill. As soon as the transmission shifts down, and engine revs up, the noise is gone. It’s mainly there when the engine is lugging and under load. I didn’t notice the noise when it was new but has become more noticeable with 25,000 miles on it.

Any ideas what it could be?

 

[Stbentoak]

I have a 2023 GMC Yukon Ulimate Denali diesel. I love the Duramax engine. Would take it over a 6.2 gas any day.
I also have noticed a rattle or rumble coming from the backside of the engine, possibly exhaust system when the engine is running around 1500 rpm and is put under load. For example, starting to climb a hill. As soon as the transmission shifts down, and engine revs up, the noise is gone. It’s mainly there when the engine is lugging and under load. I didn’t notice the noise when it was new but has become more noticeable with 25,000 miles on it.

Any ideas what it could be?

I have the same type of rattle that is more evident when it is at idle.....it sounds like it is coming from the passenger left knee footwell. Soon as I touch the throttle it stops. I've had it for the last couple of years and just lived with it, I often thought it was possibly the DEF injector. I don't really know but I'm not willing to tear into the center console to figure it out.

 

[StephenPT]

I have a 2023 GMC Yukon Ulimate Denali diesel. I love the Duramax engine. Would take it over a 6.2 gas any day.
I also have noticed a rattle or rumble coming from the backside of the engine, possibly exhaust system when the engine is running around 1500 rpm and is put under load. For example, starting to climb a hill. As soon as the transmission shifts down, and engine revs up, the noise is gone. It’s mainly there when the engine is lugging and under load. I didn’t notice the noise when it was new but has become more noticeable with 25,000 miles on it.

Any ideas what it could be?

I have this noise as well. Basically the engine is lugging itself and there's a "rattle" sound that goes with it. I don't believe it's anything loose, just inherent to the engine and the way it runs. Keep in mind this engine likes to and has no problem running in higher gears. Mine is up to 9th gear by the time I'm at 50mph and then goes to 10th right around 60mph. 85% of peak torque is at 1250rpm and it's 100% by 1500rpm.

I would also say that after 17K miles on ours it's maybe a bit louder than when it was brand new... still, the engine noise is imperceptible when cruising at 70mph.