Belt squeal (?) on cold start up on 2024 Chevy 2500HD 6.6L Gasser

gastrohman · March 11, 2024

Hi guys.

I have a 2024 2500 6.6L gasser with the 10 speed now with 6k miles on the odometer. On cold start up (e.g. before heading to work in the morning, or in the afternoon on the way home), I get what I think is belt squeal. It lasts for 15-20 seconds, and it sounds much worse when I put it in R or D with my foot on the brake. (The cab is so well insulated, I have to open my door or roll down the window to hear it.)

I’ve had it to the dealer twice. First time they said they couldn’t replicate the problem, which was ridiculous because it did it when I picked it up. The second time they replaced the belt and idler pulley, but the problem persists.

I’m thinking perhaps something about the belt and pulleys is not aligned correctly?? Or could it be something internal to the transmission??

Has anyone successfully solved this problem?

Here are a couple of vids. You can hear it really start when I drop it into R and then disappear 10-15 seconds later.

https://youtube.com/shorts/0HFmp5OGIPM?si=YbCZewrJhMgLuFFx

https://youtube.com/shorts/QbSJIw1oYBo?si=DIqD6jAhsdh7QZ3q

Thanks!

lineman1234 · March 24, 2024

Get a mechanics stethoscope and have at it.

... I had to get one to find a sound that was like a barring going, but i could not find it no mater what i did. I finally thought of the mentioned stethoscope and after a bit of searching with it, found the rear small barring on the alternator was the culprit.

mrjulian416 · March 27, 2024

My 2021 with the 6 speed does the exact same thing. It's only happens when the truck is cold, but is worse when the ambient temp is warmer/hotter... if that makes sense.

It does it for 10-15 secs, is worse when in gear, not moving, just like what your videos show. It goes away quickly when I being to drive off, and never returns until it has sat for several hours. I was wondering if it was transmission related, but with the same issue in your 10 speed tells me it most likely is not.

mrjulian416 · April 8, 2024

Gastrohman... did your dealer ever figure this noise out?

CSB7071 · May 19, 2024

Has anyone had any success determining the squealing sound? Bought the same truck - 2024 Silverado 2500 - 6.6 L Gas engine. Noticed the squealing start around 500 miles. We hear it on startup especially once you hold the brake then shift into forward or reverse - last for about 30 to 45 seconds. However the same sound appears consistently while driving and you hit the pedal to accelerate. Have had it to the dealership twice which has been no help.

Pryme · May 19, 2024

Meh mine does that a little when you’re first putting it into gear and pulling out of the garage. No big deal.

lineman1234 · May 19, 2024

Like i used to say at work. ( it isnt going to get done talking about it )

So,,,, why not try some simple things. Like a spray of belt dressing, loosen the belt, turn/shake/feel all the moveable pulleys and such for a possible bad one, or an alternator barring bad.

I had to buy a mechanics stethoscope to find a sound like a barring going bad. I couldnt find that noise no mater what i did before. I loosened the belt everything moved as it was intended. I started the motor, put that cheap $14 steath on and found the rear barring of my alternator, the small one sounded bad, it moved fine, but after a new alt, noise was gone.

( this was on my other pickup, not my new cheby ) By the way, it was a lousy $55 for the core charge on the alt, so i kept it, it cost $42 to fully rebuild the oem that i just gave away a few weeks ago, after not needing it for the last 4 years. So, i should have taken the $55.

And, no noise on my 2024 6.6 gasser WT pickup, so far.

UWSkier · May 20, 2024

On 5/19/2024 at 6:01 AM, CSB7071 said:

Has anyone had any success determining the squealing sound? Bought the same truck - 2024 Silverado 2500 - 6.6 L Gas engine. Noticed the squealing start around 500 miles. We hear it on startup especially once you hold the brake then shift into forward or reverse - last for about 30 to 45 seconds. However the same sound appears consistently while driving and you hit the pedal to accelerate. Have had it to the dealership twice which has been no help.

Mine does the same. Doesn't matter how long it's been running, but if I'm going 40-50 MPH and am on and off the throttle lightly while coasting, I get the same chirping sound. It goes away with a bit of throttle or a downshift so I don't think it's belt-related. Was going to take mine in also for this.

2FarOffRoad · June 10, 2024

Any solutions?
I have this issue as well, under 1000 miles.

diyer2 · June 10, 2024

Get a mechanics stethoscope and find it or waste time with the dummies at the dealer.

Salzette · June 17, 2024

On 5/20/2024 at 1:27 PM, UWSkier said:

Mine does the same. Doesn't matter how long it's been running, but if I'm going 40-50 MPH and am on and off the throttle lightly while coasting, I get the same chirping sound. It goes away with a bit of throttle or a downshift so I don't think it's belt-related. Was going to take mine in also for this.

I have the same chirp in the same scenario you described. Did you ever take yours in for it?

UWSkier · June 17, 2024

5 hours ago, Salzette said:

I have the same chirp in the same scenario you described. Did you ever take yours in for it?

It goes in on Thursday unless something comes up.

UWSkier · June 20, 2024

On 6/17/2024 at 4:30 AM, Salzette said:

I have the same chirp in the same scenario you described. Did you ever take yours in for it?

dealer pinged me and said I'd need to leave the truck for 25 days before they could look at it... looking for different dealership, so no, haven't had it in.

Another JR · June 20, 2024

9 hours ago, UWSkier said:

dealer pinged me and said I'd need to leave the truck for 25 days before they could look at it... looking for different dealership, so no, haven't had it in.

Consumers can’t help each other if this kind of stuff is kept anonymous.