Jump to content

Recommended Posts

Posted

I have a new 22 Silverado TB with a 6.2L that has a squealing noise when I put it in drive/reverse after cold startup. Also makes the same noise when coming to a stop, and sometimes randomly when driving. I took it to the dealer and… to everyone’s surprise, I’m sure… they couldn’t hear anything. I rode with the shop foreman and shop supervisor. Foreman tried telling me, “This truck has aggressive tires, and when you come to a stop… they’re bowing in and that’s what you’re hearing.”  I basically told him I’m not an idiot, and this is definitely a mechanical noise. I took a video of my wife driving it and coming to a stop, and it’s very prevalent. I’ve done some research, and found a few people that have the same issue… but haven’t seen a solution, or no one posts updates once it’s fixed.  Or maybe it’s not? No idea. But it’s annoying, and it shouldn’t be happening. Curious if anyone else is having this issue and what the fix was, or what has your dealer told you?

 

Attached a video. Hopefully it plays for you. 

Posted

Dealers seem to have the stupidest workers of all, the idiots couldn't even tighten down an oil filter on my first oil change I drove it home and went inside for the night while it dripped oil all over my new concrete.

I have another story for the next time as well...........

Good luck with .

Posted
15 hours ago, Robby James said:

Dealers seem to have the stupidest workers of all, the idiots couldn't even tighten down an oil filter on my first oil change I drove it home and went inside for the night while it dripped oil all over my new concrete.

I have another story for the next time as well...........

Good luck with .

Yeah it was baffling. He started with tire noise, then eventually said there’s a problem that GM doesn’t have a fix for…. Which is really unacceptable. That’s just saying, “Hey folks, come buy this truck for $60k just so you can ride around and be embarrassed every time you stop at a red light.”  I’ve been doing a lot more research and it seems as if this issue has been going on since 2019 and they’re still churning these things out and turning people away when they ask for help. There’s no excuse for it. None. I understand things go wrong with vehicles, but there’s ALWAYS a solution. We’re asking them to track down a squeak in a defined space, not some impossible task that truly doesn’t have an answer. These guys need a computer or a bulletin to tell them what to replace, and that’s cringeworthy. A bulletin that tells step-by-step how to fix an issue that a real

mechanic found. I guess I just expected too much. There’s no way I’ll drive this thing longer than a year with that noise. 

  • Like 1
Posted (edited)

This is a common issue with 6.2Ls, and the dealers have no solution for. The noise stops when you put it in Manual mode, shift up to L9 and drive around.  Magically gone.  I believe its due to the DFM technology and many owners choose to get hardware to remove this "feature" such as the Pulsar LT.   

Edited from AFM to DFM.  

Edited by American Cobra
Posted

6.2s don't have AFM.  And many trucks may not have DFM either.  This is a 6.2.  Did GM finally build one that has DFM?  Only squeak I'm aware of on the 6.2 is the serpentine belt.  I listened to the video, but couldn't identify the sound that we're suppose to hear.  I have a 2020 Trail Boss LT with the 6.2.  The serpentine belt is the only squeak I had, and it did eventually go away on its own. 

Posted
11 hours ago, Transient said:

6.2s don't have AFM.  And many trucks may not have DFM either.  This is a 6.2.  Did GM finally build one that has DFM?  Only squeak I'm aware of on the 6.2 is the serpentine belt.  I listened to the video, but couldn't identify the sound that we're suppose to hear.  I have a 2020 Trail Boss LT with the 6.2.  The serpentine belt is the only squeak I had, and it did eventually go away on its own. 

I watched a video of a guy with a GMC with the 6.2 that did have DFM. No idea what the difference is between DFM and AFM, I can for sure do the research, but how would putting the truck into L9 alleviate the noise from the serpentine belt? The noise is, I guess, difficult to hear in the video…. Unless you’ve heard the noise before, then it’ll stick out. When I stop and the truck shifts back to (I’m assuming) 1st gear, it makes a clunk noise and then a metallic chirping noise. Which the metallic chirping noise could be the belt, but I’m not sure how putting it into manual mode would fix a belt squeak. 
 

Genuinely looking for info here, I’m not trying to be rude. So hopefully I’m not coming off that way. 
 

Curious, did yours squeak when you stopped too? Or was it just at a cold start up?

 

Thanks. 

Posted (edited)
13 hours ago, Transient said:

6.2s don't have AFM.  And many trucks may not have DFM either.  This is a 6.2.  Did GM finally build one that has DFM?  Only squeak I'm aware of on the 6.2 is the serpentine belt.  I listened to the video, but couldn't identify the sound that we're suppose to hear.  I have a 2020 Trail Boss LT with the 6.2.  The serpentine belt is the only squeak I had, and it did eventually go away on its own. 

 

 

The 6.2 have DFM and are NOT affected by the chip shortage.  Only the L84 5.3 is affected.  

Edited by newdude
Posted
1 hour ago, JoshRM said:

No idea what the difference is between DFM and AFM

What Is The Difference Between Afm And Dfm? When your engine is running at a low load or cruise speed, AFM shuts off half of its cylinders to reduce fuel consumption. DFM allows the engine to turn off two cylinders, four cylinders, or any of the eight cylinders it sees as necessary to meet the current and future needs of the engine.

Posted (edited)
2 hours ago, JoshRM said:

I watched a video of a guy with a GMC with the 6.2 that did have DFM. No idea what the difference is between DFM and AFM, I can for sure do the research, but how would putting the truck into L9 alleviate the noise from the serpentine belt? The noise is, I guess, difficult to hear in the video…. Unless you’ve heard the noise before, then it’ll stick out. When I stop and the truck shifts back to (I’m assuming) 1st gear, it makes a clunk noise and then a metallic chirping noise. Which the metallic chirping noise could be the belt, but I’m not sure how putting it into manual mode would fix a belt squeak. 
 

Genuinely looking for info here, I’m not trying to be rude. So hopefully I’m not coming off that way. 
 

Curious, did yours squeak when you stopped too? Or was it just at a cold start up?

 

Thanks. 

A squeaky belt has nothing do with AFM and DFM.  Shifting into L9 won't change it.  People who refer to that solution are not talking about the noise from the belt.  However, I don't think it's a DFM issue because it's only happening on startup, not while the engine is just idling.  You indicated you have success with putting the truck in L9 and the noise went away, so it may not be a belt issue for your vehicle.  I haven't had the issue where I needed to shift into L9, so that might explain why I didn't notice the noise in your video. 

 

I can't help with the clunk noise.  Could be a number of things, none of which I've experienced in my truck, and my truck is parked on an 8% grade, nose down, nightly. 

 

Not only did my belt use to squeak on a cold startup, but also when the engine turned back on while driving after turning off at a red light.  Initial repair by dealer was to apply some sort of dry lubricant.  It reduced the squeak, but didn't eliminate it.  After awhile one edge of the belt wore enough that the squeaking went away.  Wearing is indicated on the edge, but isn't severe enough for me to be concerned about breaking.  Obviously a pulley is slightly out of alignment with the others, but the belt could be a smidge too wide, too.

Edited by Transient
Posted
38 minutes ago, newdude said:

 

 

The 6.2 have DFM and are NOT affected by the chip shortage.  Only the L84 5.3 is affected.  

Thanks for correcting me on that

Posted
3 hours ago, It's Tim said:

Engine/trans mount.

Did you have this issue and that fixed it? Again I have to ask how switching to manual mode would alleviate a bad mount. I guess it’s possible that it shifts from 2nd to 1st harder when not in manual mode causing a shake, but I would think mounts would make noise all of the time and not just sometimes at specific points. Genuinely don’t know, though. 

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
  • Latest Articles

  • Posts

    • Have considered installing a DC to DC charger in your camper to replace your isolator?  
    • Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      
    • Hello from Australia Just sharing that there is now a way to delete the active shutters entirely with just a plug in module. Opens up tons of room to light bars etc.
    • I have an observation and a question... 1) I watch the voltage closely because I have had to dial in the cut-in/cut-out voltages of the battery separator to my camper.  The "smart" charging drives me nuts.  Anyway, I noticed that when coasting for a while, and especially if lightly using the brakes (though not necessary), the voltage goes up from mid/high-13 volts to mid/high-14 volts.  Then it drops back down after stopping or going again.  Consistently!   The only explanation I can come up with is REGENERATIVE BRAKING!  Well, maybe that's a little bit of an exaggeration, but it's certainly free extra battery charging.   2) Driving on mountain roads I will use L and vary the max gear.  Things straighten out and I end up in L10.  Sometimes I leave it there for a while.  Is there any difference between L10 and D?   
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...