2019 Silverado cabin rumbles when slowing down

STX30MAC · February 9, 2020

Took mine in today for some recalls and tire balance. They got done 2hrs before I could get back and I told them to drive it around and see if they felt anything off when stopping. They said they feel it but have no idea what could be causing it. I told them about stopping with being in neutral how you don’t feel it as well. They don’t have a fix or know what causes it.

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hotrodz37 · February 9, 2020

Took mine in today for some recalls and tire balance. They got done 2hrs before I could get back and I told them to drive it around and see if they felt anything off when stopping. They said they feel it but have no idea what could be causing it. I told them about stopping with being in neutral how you don’t feel it as well. They don’t have a fix or know what causes it.

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Yeah they did a bunch of tests on mine over the course of a week and relayed everything to GM and gm came back with “operating as designed”. Such BS. I’ve driven a lot of cars over the years and not one of them has ever done this. Such a cop out on General Motors part. Can’t believe after all this time they still can’t figure out how to build a transmission properly.

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lapoolboy · February 10, 2020

On 2/9/2020 at 9:17 AM, hotrodz37 said:

Can’t believe after all this time they still can’t figure out how to build a transmission properly.

It may not even be the transmission. My testing leads me to believe it is in the driveshafts.

hotrodz37 · February 10, 2020

Just now, lapoolboy said:

It may not even be the transmission. My testing leads me to believe it is in the driveshafts.

Mine truck is 2wd and doesnt do it in neutral. You're referring to your front drive shafts right?

I think mine is 100% the tq converter or something to do with the DFM.

lapoolboy · February 10, 2020

Just now, hotrodz37 said:

Mine truck is 2wd and doesnt do it in neutral. You're referring to your front drive shafts right?

I think mine is 100% the tq converter or something to do with the DFM.

Nope, the rear driveshaft. I experimented with all sorts of pinion angles and I was able to make the problem better/worse. Putting it in neutral takes the driven torque off the driveshaft and makes the problem go away. GM has 2.5 deg. shims in some trucks and none in others trying to solve the problem. Pro-Comp and Zone both mention this "inherent vibration" in the T1 trucks in their instructions. I will live with it unless/until GM figures out how to easily fix it.

hotrodz37 · February 10, 2020

1 minute ago, lapoolboy said:

Nope, the rear driveshaft. I experimented with all sorts of pinion angles and I was able to make the problem better/worse. Putting it in neutral takes the driven torque off the driveshaft and makes the problem go away. GM has 2.5 deg. shims in some trucks and none in others trying to solve the problem. Pro-Comp and Zone both mention this "inherent vibration" in the T1 trucks in their instructions. I will live with it unless/until GM figures out how to easily fix it.

Good info here, thanks for sharing. I've just kind of learned to live with it. I have to take mine back in for the leaking rear window today and I'll see if the loaner I get does it and if it has shims or not. Wonder if pulling the driveshaft and turning it 180 might make it better or worse. I'm also planning on leveling mine once I get the other issues sorted out - I know a 2" level doesn't change the pinion angle much if at all but might help or make worse, who knows.

Doesn't seem like many people have this issue with the 10 speed tranny though, which might be using the same drive shaft.

Annoying nonetheless. Sometimes mine is pretty bad, others it's not, wondering if it's the ambient temp.

lapoolboy · February 10, 2020

3 minutes ago, hotrodz37 said:

Doesn't seem like many people have this issue with the 10 speed tranny though, which might be using the same drive shaft.

I have the 6.2/10-speed and I DEFINITELY have the problem.

hotrodz37 · February 10, 2020

1 minute ago, lapoolboy said:

I have the 6.2/10-speed and I DEFINITELY have the problem.

Well shit man, you're just proving me all kinds of wrong this morning

I had an brand new expedition rental this weekend (6 miles on the clock) and it had the 10-speed, smooth as can be. Might be onto something with the driveshafts/pinion angles being different.

Luckyfd · February 10, 2020

I had the same issue. Service dept told me it was my tires...obviously it wasn’t but it’s documented so well see

romclean1 · February 12, 2020

I have the 6.2 10 speed and the vibration didn’t occur until after the 2” lift was installed. But then I put more aggressive tires on and it’s hard to tell now.

Rparks1 · February 17, 2020

Yes mine is the worst Chevy i have ever had! This is my 24 new chevy and i hate the "SLOW" down 38 MPH to 10 MPH HARMONIC-VIBRATION-NOISE! Its not normal-right......And im a BIG Chevy guy! Very upset!

lapoolboy · February 26, 2020

Have any of you who have had their trucks into the dealer for this issue gotten any feedback on it?

I'm starting to think maybe it's in the rear diff??? I've not read anyone mention this.....wondering if GM didn't fill it properly or something.

hotrodz37 · February 27, 2020

Have any of you who have had their trucks into the dealer for this issue gotten any feedback on it?

I'm starting to think maybe it's in the rear diff??? I've not read anyone mention this.....wondering if GM didn't fill it properly or something.

You might be onto something - or the pinion angle like you said. Considering it’s affecting 10-speeds and 8-speeds guess it’s not the transmissions.
@lapoolboy did you try the range device yet to rule out DFM?

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lapoolboy · February 27, 2020

6 minutes ago, hotrodz37 said:

You might be onto something - or the pinion angle like you said. Considering it’s affecting 10-speeds and 8-speeds guess it’s not the transmissions.
@lapoolboy did you try the range device yet to rule out DFM?

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I have not tried Range device yet - I am still deciding how I want to do it with my Amp steps also needing to be plugged into the OBD2 port. I may just unplug them temporarily to run the Range and see what happens. I'm betting it won't help. I'm tempted to pull the plug on the rear diff to check fluid level.

hotrodz37 · February 27, 2020

I have not tried Range device yet - I am still deciding how I want to do it with my Amp steps also needing to be plugged into the OBD2 port. I may just unplug them temporarily to run the Range and see what happens. I'm betting it won't help. I'm tempted to pull the plug on the rear diff to check fluid level.

Yeah it will be interesting - ya never know. Just thinking things that are in common on our trucks with different motors and transmissions that both do it. Rear diff, pinion angle off, DFM, do both 8 and 10 speed trannys use the same torque converter?

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