Jump to content

Normal L8T noises?

BuckWallace

By BuckWallace
in 6.6L Gas V8 (L8T)

 Share

Recommended Posts

Aimatdeer Enthusiast

Aimatdeer

Posted
Posted

I have a 24 since August. If I don't have the radio on lightly accelerating I can barely hear a whine/whir in what seems like 5th and 6th gear. Radio on even low volume can't hear it. Accelerating a little harder doesn't seem to be there. Hopefully normal.

  • 10 months later...
  • Replies 36
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Another JR
Another JR

Planetary gear sets are particularly noisy because of the sympathetic vibration of multiple gear sets of identical design generating reinforcing noise energy. It’s a common, known issue with helicopte

switters
switters

They did! Sold me a NEW 2024 for only a little more than the pre-owned 2024 I bought with the transmission issue. All's well that ends well! 😀

Byrds8
Byrds8

https://static.nhtsa.gov/odi/tsbs/2024/MC-11012007-0001.pdf   It has a few items on this list but about youre looking for the below portion.   Reaction Gearset Whine (Gearset One)

Graves Enthusiast

Graves

Posted
Posted (edited)

I have a 2024 2500HD 6.6 gas and I am getting the same whining noise, but mine has gotten louder over time, used to only hear at slower speeds just starting out, now it is louder and here it almost all the time, going into the dealer next Monday, see what they say.

 

Edited by Graves
  • 2 months later...
lineman1234 Enthusiast

lineman1234

Posted
Posted

Almost 50,000 on my 2024. No motor noises at all, just smooth. 

 

Same no worse no better transmission sound/s it made from new.

  • Like 1
  • 4 weeks later...
OS RR Enthusiast

OS RR

Posted
Posted (edited)

Aside from a slight wine from the transmission (that's remained constant since new, so I don't worry about it) and to be honest, it could be the power steering pump too. I haven't cared to dig into it.

 

Engine makes some general bottom end "running engine" noise. I pay no attention to it.

 

24 w/ ~16k miles. Daily driven since the day I bought it.

Edited by OS RR
  • 1 month later...
Rickochet Enthusiast

Rickochet

Posted
Posted

My 2026 Silverado 2500 Hd 6.6 Gasser has the same noise.  It is especially prominent at 2,000 RPM's.  Everyone I had ride with me asks, "Wow, that turbo sounds mean!"  It's embarrassing to say, "Sorry, that's not a turbo, because it doesn't have one.  Unfortunately, GM says it's normal transmission noise."  They usually respond with,  "Wow, I'm not buying a GM truck!!"  It's so sad that GM has this attitude on my brand new truck with only 3,000 miles on it, and it made that noise on my test drive and remains today.  I'm at the dealership right now to get it checked again.  I'm also going to drive another new 2500 HD to see if it makes the same noise.

 

PLEASE NOTE:  GM, I am truly disappointed with this type of quality control and customer service.  

  • Like 1
Byrds8 Enthusiast

Byrds8

Posted
Posted

Mine has made the same noise since new. There is a TSB about it. My dealership said the same thing, it's normal. Its generally around 3rd to 4th gear and its gone around 38mph.

Another JR Senior Enthusiast

Another JR

Posted
Posted

Planetary gear sets are particularly noisy because of the sympathetic vibration of multiple gear sets of identical design generating reinforcing noise energy. It’s a common, known issue with helicopter main rotor drive transmissions. However, the designer/builder should be taking comlonly known design measures to minimize the noise. For GM to simply say “normal noise” for a particularly noisy gear set is to ignore the engineering/builder challenge to minimize noise for such gear sets, and indicates laziness and lack of care.  
 

Unfortunately as a consumer all we typically can do is vote with our dollars. As a professional aviation systems analyst with vibration and noise expertise, I have become so disgusted with current automotive manufacturers that the rule I follow is not to buy any product that doesn’t have at least a ten-year track record. We cannot rely on the integrity of manufacturer’s engineering organizations to put out good products, and can only rely on demonstrated reliability. It’s sad, but they asked for it. 

  • Like 4
  • Thanks 1
Rickochet Enthusiast

Rickochet

Posted
Posted
14 hours ago, Byrds8 said:

Mine has made the same noise since new. There is a TSB about it. My dealership said the same thing, it's normal. Its generally around 3rd to 4th gear and its gone around 38mph.

Do you have the TSB or a link to it? 

Rickochet Enthusiast

Rickochet

Posted
Posted
12 hours ago, Another JR said:

Planetary gear sets are particularly noisy because of the sympathetic vibration of multiple gear sets of identical design generating reinforcing noise energy. It’s a common, known issue with helicopter main rotor drive transmissions. However, the designer/builder should be taking comlonly known design measures to minimize the noise. For GM to simply say “normal noise” for a particularly noisy gear set is to ignore the engineering/builder challenge to minimize noise for such gear sets, and indicates laziness and lack of care.  
 

Unfortunately as a consumer all we typically can do is vote with our dollars. As a professional aviation systems analyst with vibration and noise expertise, I have become so disgusted with current automotive manufacturers that the rule I follow is not to buy any product that doesn’t have at least a ten-year track record. We cannot rely on the integrity of manufacturer’s engineering organizations to put out good products, and can only rely on demonstrated reliability. It’s sad, but they asked for it. 

Another JR, So true, and thanks for sharing your wisdom!  The whine sounds like an old-school radio whine from an aftermarket radio that was installed with a poor ground.  Not something that we should expect from an $80,000+ truck.  I believe that GM monitors these forums, maybe I will receive a call...  Time will tell.

Byrds8 Enthusiast

Byrds8

Posted
Posted
50 minutes ago, Rickochet said:

Do you have the TSB or a link to it? 

https://static.nhtsa.gov/odi/tsbs/2024/MC-11012007-0001.pdf

 

It has a few items on this list but about youre looking for the below portion.

 

Reaction Gearset Whine (Gearset One)

With variation in gear tooth finish and positional control, some customers may experience whine from the reaction

planetary gearset during light to moderate driving conditions.

Most common conditions to hear whine from the reaction gearset is in 4th and 5th gear (20-35 MPH) (32-56 KPH).

Reaction gearset is active in gears 3-6 and 8-10 so depending on severity it may be possible to hear in gears other

than 4/5.

Frequency of whine will change as transmission shifts gears due to component rotation speeds being changed.

Utilizing manual tap to shift through gears is a good way to verify what gears whine in present in.

Note: Whine from the reaction gearset should not be present in 7th gear due to the 1:1 ratio and gears being locked.

If whine is present in 7th gear, issue likely lives with some other component.

  • Like 2
OS RR Enthusiast

OS RR

Posted
Posted
1 hour ago, Byrds8 said:

https://static.nhtsa.gov/odi/tsbs/2024/MC-11012007-0001.pdf

 

It has a few items on this list but about youre looking for the below portion.

 

Reaction Gearset Whine (Gearset One)

With variation in gear tooth finish and positional control, some customers may experience whine from the reaction

planetary gearset during light to moderate driving conditions.

Most common conditions to hear whine from the reaction gearset is in 4th and 5th gear (20-35 MPH) (32-56 KPH).

Reaction gearset is active in gears 3-6 and 8-10 so depending on severity it may be possible to hear in gears other

than 4/5.

Frequency of whine will change as transmission shifts gears due to component rotation speeds being changed.

Utilizing manual tap to shift through gears is a good way to verify what gears whine in present in.

Note: Whine from the reaction gearset should not be present in 7th gear due to the 1:1 ratio and gears being locked.

If whine is present in 7th gear, issue likely lives with some other component.

 

 

Mine has what I think is general pump whine. But also does this, not sure what gear. Sounds like a power steering pump groaning when it shifts. Pretty random as to when it happens. Usually coming down hill and it up shifts.

Rickochet Enthusiast

Rickochet

Posted
Posted
21 hours ago, Byrds8 said:

https://static.nhtsa.gov/odi/tsbs/2024/MC-11012007-0001.pdf

 

It has a few items on this list but about youre looking for the below portion.

 

Reaction Gearset Whine (Gearset One)

With variation in gear tooth finish and positional control, some customers may experience whine from the reaction

planetary gearset during light to moderate driving conditions.

Most common conditions to hear whine from the reaction gearset is in 4th and 5th gear (20-35 MPH) (32-56 KPH).

Reaction gearset is active in gears 3-6 and 8-10 so depending on severity it may be possible to hear in gears other

than 4/5.

Frequency of whine will change as transmission shifts gears due to component rotation speeds being changed.

Utilizing manual tap to shift through gears is a good way to verify what gears whine in present in.

Note: Whine from the reaction gearset should not be present in 7th gear due to the 1:1 ratio and gears being locked.

If whine is present in 7th gear, issue likely lives with some other component.

 

Thanks so much for the information, Byrds8.  I have the noise in Park or while driving, especially loud at 2,000-2,500 RPM.  According to the TSB, the most applicable condition is this one:

 

Park Transmission Oil Pump Gear Mesh Whine Unlike previous generation HD transmissions (6 speed), the 10 speed Allison model transmission utilizes a (3) spur gear design (driven off of the torque converter) to drive the transmission oil pump. Due to the 3–spur gear design, some transmissions may exhibit a whine noise while in park or driving and may get louder as engine speed or transmission temperature increases. Isolating the whine to the oil pump gears can often be done by replicating the complaint in park and sweeping engine speed slowly from base idle to 2500 RPM. If whine can be reproduced in park, replacement of the transmission front support and/or transmission oil pump often corrects the whine complaint.

  • Like 1
Rickochet Enthusiast

Rickochet

Posted
Posted
On 2/17/2026 at 6:34 PM, Byrds8 said:

Mine has made the same noise since new. There is a TSB about it. My dealership said the same thing, it's normal. Its generally around 3rd to 4th gear and its gone around 38mph.

Did you have your noise repaired or just living with it?

Byrds8 Enthusiast

Byrds8

Posted
Posted
1 hour ago, Rickochet said:

Did you have your noise repaired or just living with it?

Since I’ve seen a lot of posts mentioning this noise and GM seems to elude to its normal, I am just leaving it be. If it gets worse with time etc I’ll make them do something. I didn’t want them to swap the transmission out if the next one was going to do the same thing. 

  • Like 1
Pryme Senior Enthusiast

Pryme

Posted
Posted
On 2/18/2026 at 8:32 AM, Rickochet said:

Another JR, So true, and thanks for sharing your wisdom!  The whine sounds like an old-school radio whine from an aftermarket radio that was installed with a poor ground.  Not something that we should expect from an $80,000+ truck.  I believe that GM monitors these forums, maybe I will receive a call...  Time will tell.

Oh man I remember that sound from back in my car audio days. That would drive me up a wall. I don’t think this sound has to do with the 6spd. I’ve never heard it.  Must be 10spd only?

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • garagerog
      Low fuel pressure after installing new fuel pump

      By garagerog · Posted

      Replace the fuel pump with an OEM AC-Delco.
    • Gilkey96
      Low fuel pressure after installing new fuel pump

      By Gilkey96 · Posted

      Hello, first time posting here. I have an 03 Chevy 1500HD with the 6 liter gas engine. The truck ran fine until the fuel pump died on me and had to get it towed. Replaced the fuel pump with a precision pump from O’rileys and changed the fuel filter while I was there. The truck will run and drive now but it wants to idle around 500 rpm when in drive and it tries to stall if you touch the gas. It drives fine though, just doesn’t want to idle. Put a fuel pressure gauge on the rail and only have 50 psi. I guess these trucks should have 55-62 psi to run right. I thought the regulator might be the issue because when I would unplug the vacuum hose it jumped to 56 psi. Replaced the regulator and no change. The only thing I can think of is that I was sold a faulty fuel pump. Any help would be appreciated because I’d rather not have to take the bed off again if I don’t have too. Thank you!
    • diyer2
      AFM Experience

      By diyer2 · Posted

      I've been wrenching on GM trucks for 17 years. And I need to get something off my chest because it's been weighing on me for a long time. After all that time, all those motors, all those people standing in my bay, I've figured out there are really only two kinds of owners. The ones who already know about this. And the ones who are about to find out the hard way. A guy came into my shop a few weeks back in a 2018 Silverado 5.3. Sharp guy, maybe 35. Knew his truck cold. He'd been on the forums, read the threads, done his homework. He only rolled in so I could double-check a little module he'd already plugged in himself. Wanted a second set of eyes on it. Ten minutes, in and out, drove off happy. Two days later, a completely different story walked through the same door. Older fella this time, in a 2016 Sierra. Gorgeous truck, clearly babied, not a scratch on it. Wedding ring. Looked like a guy who took care of his stuff. He was in because his engine had started knocking on the way to work. And by the time I got the valve cover off, I already knew it was too late. Lifter collapsed. Cylinder 5. Camshaft chewed up. The whole top end shot. Same kind of truck. Same motor. Same roads, probably the same dealer. The only thing separating those two men was information. I've been at this since 2008, and I've worked on everything GM puts out. Silverados. Sierras. Tahoes. Yukons. Suburbans. Escalades. The 5.3 and the 6.2. Doesn't matter which badge is on the tailgate. They all carry the same problem. So here's the information one of those guys had and the other one didn't. It's called Active Fuel Management. AFM. GM started building it into their V6s and V8s back in 2007 to squeeze out a little better mileage on the highway. Maybe a mile or two a gallon. All to hit government fuel economy numbers. The way it works, the motor quietly shuts down half its cylinders when you're just cruising along. And the little lifters that pull that off have a tiny pin inside them that's constantly clicking in and out. Lock, unlock, lock, unlock. Hundreds of times a drive. Thousands of times a week. Eventually one of those pins wears through. The lifter drops. And it starts grinding the camshaft down like a chisel on butter. And what nobody tells you is that the shudder you feel around 40 or 50 mph? That's the system cycling. Every single time. Here's what really gets me. The pre-2007 trucks, the ones without AFM, they're bulletproof. I've got customers still daily driving them with 260,000 miles on the odometer. Not a problem in the world. GM took a perfectly good motor that would have lasted a lifetime and bolted this system onto it. And it is wrecking engines that should have run forever. The guys who hang around the forums already know all of this. So do the techs. They handled this years ago. They didn't sit around waiting for the dealership to mail them a warning letter, because that letter is never coming. It's the guys who figured somebody would've told them who end up on my lift. And I want to be clear, because this part matters. Maintenance has nothing to do with it. I've torn down motors with barely 30,000 miles on the clock. I pulled apart a Tahoe last summer with 24,000 on it. Practically a brand new truck. Owner had it less than a year. Spotless oil. Best synthetic money can buy, changed early every time. Made no difference. I've seen guys with full dealer records, every interval stamped. Made no difference. The oil changes were never the problem. The pin was. And no amount of babying that truck stops that pin from cycling every single time you drive. That's the part that eats at me. These are good motors. Take the AFM out of the equation and a 5.3 or a 6.2 will run 300,000 miles and never blink. So a few years ago I started telling every single owner who comes through my doors the exact same thing the smart guys already knew. Get yourself a FullForce disabler. It plugs right into the port under your dash. Couple of seconds and you're done. It just tells the computer to leave every cylinder running, full time. No more cycling. No more beating those lifters back and forth every time you turn the key. It doesn't reprogram anything. Doesn't touch your tune. And unplug it before a dealer visit and there's absolutely zero trace it was ever installed. I've had customers come back at 40,000, 60,000, 80,000 miles after I put one in. Zero issues. The trucks run smoother. And the lifters aren't getting beaten to death every single drive. I won't sit here and tell you it's magic. A lifter that's already damaged is a lifter that's already damaged, and this won't un-ring that bell. But it takes away the one thing causing all that wear in the first place. That's the whole game. You don't need a five-thousand-dollar delete. You don't need an expensive tune. You don't need to tear anything apart. You just need to stop the cycling. I'm not writing this for any company. I'm writing it because I'm tired of watching the guys who didn't know pay four and five figures for it. I'm tired of being the guy who has to break the news. I'm tired of knowing that the guys who did know fixed the whole thing for the price of a tank of gas, and the only difference was that somebody told them first. If you drive a Silverado, Sierra, Tahoe, Yukon, Suburban, or Escalade from 2007 or newer with a V6 or V8, you've got AFM. You've got those lifters, and they're cycling every single time you drive. So be the guy who already knew. Not the one I'm scraping metal out of next month. EDIT: A bunch of folks asked, so here it is. The one I put my faith in is FullForce. This is where to find it: https://www.tryfullforce.com/products/fullforce™-afm-dfm-disabler They back it with a 60-day guarantee too. I've handed out more than I can count and not one's ever come back to me. Not one. See less
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Thanks for following along. I'm not author material, my tenses are all over the place and an editor would have a heck of a time cleaning up after me. Reading and writing is still a fun pastime though.   My new scanner came in yesterday, wow, where the heck has this thing been?! It connects right up to the Blazer, there's all kinds of bidirectional tests like EGR activation and percentage, toggle the fuel pump relay, EVAP purge valve, IAC control, AC relay, reset the transmission's adaptive learning, toggle shift solenoids and TCC lockup, and I can reset fuel trims with the click of a button...all things I could have used over the last 60 days!   It's also telling me there is a stored code in the ABS module for front left wheel sensor open and something about the brake switch. The ABS dash light works. It illuminates normally during the self-test at key on/ start and that's it. I cleared the codes and will see if they set when I take it out later. That, and I'm going to get (hopefully) real data on timing and cam ******. The PID's are there.   I connected the tool to my truck...holy smokes. Newer vehicles make early OBDII vehicles look like 8-bit, pixelated, early Nintendo stuff. This? This is like wearing 3D virtual reality goggles playing one of those elaborate, cinematic video games with seasons and plots in comparison. There are SO MANY modules and SO MANY tests and SO MUCH data. There's a scanner sequence for filling the coolant...   End of the day, it's a tool with way more power than I need, but the versatility to do old and new is there (and I need an adapter to connect it to my OBDI Camaro). It will allow me to do the first pass of diagnosis when out-of-warranty vehicles need help, and it will enable more DIY maintenance like brake system bleeding, ABS bleed, etc. I probably over-bought here, but, mission is accomplished.   Enjoy your Sunday...I need to shut this machine down and go get ready for the week ahead.
    • MORSNO
      Which 2027 engine will you choose?

      By MORSNO · Posted

      Not that I've read, after all the issues they've had in the past I'm pretty sure they learned their lesson. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...