Jump to content

2021 GMC Sierra near dash rattle

EmporerM
 Share

Recommended Posts

EmporerM Enthusiast

EmporerM

Posted
Posted (edited)

I have scoured the forums for this issue. It seems to be common among other truck owners but none of their solutions have proven to me my same cause. I’m hoping to bring some new light to this issue. I am a little late into the game.  Just bought a 2021 GMC Sierra AT4. I have the same rattle: so far I have removed the cluster and added rattle prevention to the AC duct. I have firmly secured the hood release pull cord all the way from the inside to the hood latch. This rattle is driving me insane and the dealership (despite have a new vehicle warranty) charges me $150 anytime I bring it to the shop with this issue. They claim its a harness loose but do not know “which” one or “where”. Any solutions would be MUCH appreciated. The coolant reservoir was missing a bolt. After bolting it down with felt washers on both sides, still no rattle solution.

 

any images/picture to help navigate would be awesome

 

Edit: I have completely secured the transmission harness. This is not the source of the rattle. It sounds like it’s coming from behind the cluster area. When I had it taken apart I could not recreate the sound. I feel like it has to be in the engine bay somewhere

Edited by EmporerM
Adding information
kickass audio Enthusiast

kickass audio

Posted
Posted

is this when listening to music or just driving? I have a rattle depending on the song that is playing and i found both my front doors were a big source of the rattle so I fixed that by loosening the 2 screws where your hand goes to pull the door closed and pushing the door panel closer to the window and tightening the 2 screws down. i  then noticed a smaller rattle sound on the dash where the defrost vent and the heads up display (in my case it's just the little red lights for the collision avoidance system) and tapping on the plastic above the instrument cluster sits fixes the issue for a little. I need to eventually pull the cover off and add some felt tape to it to stop the rattle but it's not that big of a deal for me.

EmporerM Enthusiast

EmporerM

Posted
  • Author
Posted

This rattle only happens when I hit 50MPH and gets worse the faster I drive.  Even when the radio is on and I’m at a complete standstill, no rattle. As soon as I hit 47 MPH the rattle begins. At 70 MPH I have to crank my radio up almost 30% up to drown out this noise. 
 

when I get home today I am gonna explore maybe the transmission harness. I’ve seen where there was a GM bulletin put out for it a few years ago

EmporerM Enthusiast

EmporerM

Posted
  • Author
Posted

FOR THE LOVE OF GMC, the rattle has been found and fixed. One of the screws holding the fender well up was missing. The metal clip that sits in the metal bracket got wind on it at higher speeds. Put a piece of tape over the clip and a new screw in it. Wallahhh.. no more rattle. One key point that made me look there was: the rattle went away even at high speeds when it was raining. The weight of the water on the clip and fender well prevented the metal on metal rattle at higher speeds. I’ve got a video of what it sounded like for anyone hunting a sound. 

  • 1 year later...
SummitSierra117 New Member

SummitSierra117

Posted
Posted

Do you have pics of the missing screw and fender well? I have the same rattling noise at highway speeds (50-70mph) and just noticed that it went away yesterday driving in the rain. Thanks.

SummitSierra117 New Member

SummitSierra117

Posted
Posted
On 2/5/2024 at 7:48 PM, EmporerM said:

FOR THE LOVE OF GMC, the rattle has been found and fixed. One of the screws holding the fender well up was missing. The metal clip that sits in the metal bracket got wind on it at higher speeds. Put a piece of tape over the clip and a new screw in it. Wallahhh.. no more rattle. One key point that made me look there was: the rattle went away even at high speeds when it was raining. The weight of the water on the clip and fender well prevented the metal on metal rattle at higher speeds. I’ve got a video of what it sounded like for anyone hunting a sound. 

Do you have pics of the missing screw and fender well? I have the same rattling noise at highway speeds (50-70mph) and just noticed that it went away yesterday driving in the rain. Thanks.

Tom73 Enthusiast

Tom73

Posted
Posted

I had a rattle like that. Sounded like a noise in the B pillar. Searched all over, thought maybe the retractable step board but all were tight. Dealer found it, screw loose in the mud flap area at the rear of the front wheel well   Tightened the screw and noise went away. 

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted
On 5/29/2025 at 9:55 PM, SummitSierra117 said:

Do you have pics of the missing screw and fender well? I have the same rattling noise at highway speeds (50-70mph) and just noticed that it went away yesterday driving in the rain. Thanks.

We'd like to look into this rattle, and connect you to a dealership who can take a look. Please email our team at [email protected] with your VIN and we can get started. By sending us a message, you consent to the information you provide being monitored and recorded by GM or those acting on GM’s behalf, subject to the GM Privacy Statement: https://www.gm.com/privacy-statement.

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

    • newdude
      Transmission Woes :-(

      By newdude · Posted

      You need a better code reader/scanner.  You are missing codes.  Did the dealer give you a copy of the SAVI scan from that visit?     If the fluid hasn't been changed, change it.  Shudder will likely go away.  
    • newdude
      Can anyone decode a VIN to determine if this truck has had emissions issues or a recall?

      By newdude · Posted

      TLDR to my other post...   Hard. Pass.  Too many what ifs.     Are you set on a 3.0 Duramax?  Have you considered anything not GM just in case?  If you don't have to have a pickup, lots of other options for $27,000 out there.   
    • newdude
      Can anyone decode a VIN to determine if this truck has had emissions issues or a recall?

      By newdude · Posted

      I see some red flags.   - No mention in the Carfax if the oil pump belt was changed.  LM2s had a 150,000mi service interval, and its got 164,245mi on it.  So right out the gate it needs about $3000-3500 for that to be done before driving it another 150,000mi.  Belt is at the rear of the engine.     - If something happens to the transmission valve body, the special coverage is expired by mileage.  That will likely be an out of pocket expense, with zero or near zero GM participation if something happened even though its in by time.   - 2020 LM2s seem to need timing chains after 80,000mi at some point.  They fixed this end of 2020/starting 2021 model year engines.  They will usually set a P0016 I think?  There is another $8000-10,000 if it needs a chain.  The main chain is at the back, secondary at the front so the pump belt would be done at the same time if it needed chains.     - Long oil change intervals.  7,000-8,000mi on average, probably close to 0% or perhaps to or beyond 0% on the OLM.  Lots of them not at the dealer which makes me wonder how much of the oil ran through that truck was the proper Dexos D rated 0w20 oil and not just gas engine 0w20, which is not the same at all.     - Long fuel filter changes, again likely taking the fuel filter life to 0% or more.  First one went 28,603, second was done 43,094 miles later at 71,697, from there another 46,452mi to 118,149mi, and then the most recent one 37,026mi later at 155,175mi.  So counting its original fuel filter, its had only 4 fuel filters on it.  No bueno IMO.         Good news?    - It has had only two warranty trips to the dealer.  The first free service (end of December 2020 on the Carfax), and the transmission reprogram recall (end of August 2025 on the Carfax).     - Truck did a LOT of moving, so that might explain the lack of emissions related repairs like bad NOX sensors, bad exhaust temp sensors, bad glow plugs, etc.         The "emissions system checked" could just be how something was flagged for Carfax.  GM dealers have to do SAVI reports for warranty repair orders so they scan the truck.  So its possible that is there for that?  
    • cherryred21duramax
      Can anyone decode a VIN to determine if this truck has had emissions issues or a recall?

      By cherryred21duramax · Posted

      Thank you, @Z45!   NOTE - No all repair shop/Dealers reports to Carfax   That is my main concern.  The CARFAX looks way too clean for a 6 year old anything with 164,245 miles.  Even something known for reliability (like many Toyotas) typically has a lot more replaced, like a Nav screen, interior trim, shock/strut, or brake pads.  And surely the last set of tires (installed at ~58k miles) would be bald unless those were all highway miles.   I'm tempted to pay a local dealer to look up the VIN, but am not sure if that will be worthwhile.  Last time I did this, it was 100% useless, and I felt scammed - they noted the bumper was replaced years ago and that's it.  A 5-year old could spot the accident damage, even though nothing was on the CARFAX.   After giving the dealer a call, the truck may have a hard shift, but they have to verify with their mechanic if that's even a concern.  And I've test driven about a dozen of these now, many near Chicago, and half the trucks shift hard/odd at all throttle positions.  The ones with aftermarket lifts/larger tires shift terrible, and 3 stock trucks shifted so violently I thought the transmission valve body was going out.   At this point I'm conflicted, as I need a vehicle, and am coming up short locally.  Northern trucks in this price range tend to have either multiple owners, a lot of mods (lifts/oversized tires without re-gearing), and are generally in rougher shape.   If this truck showed up in your neighborhood for $27k and you had to purchase it sight-unseen, with the possibility of needing a 10L80 rebuild, torque converter, or rear end - would you do it?  I'm convinced most of the 10L80 trucks I test drove are broken, they can't all shift so bad, with massive flares/slipping/lurching and mis-matched downshifts like a teen driver learning stick.
    • Griffin Donovan
      2027 GMC Sierra Spot Shots + Undisguised Interior (BIG Changes!)

      By Griffin Donovan · Posted

      From the spy shots, the front end does look like it's borrowing some styling cues from the Canyon. I'm more interested in the powertrain news than the screens though. If the 3.0 diesel survives into the next generation, that alone will keep a lot of current owners interested.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...