Jump to content

Recommended Posts

Posted

Mine has been clunking and really is bad!!I have 7000 miles on it and it is kept in garage.

Posted

They called me yesterday and said it was a faulty "electronic brake module" and they replaced it. They said they could not reproduce the metallic clanking or the vibration.

 

When I got to the dealer to pick it up it was after hours so I dropped the rental truck gets in the mail slot and got in my truck to leave. I immediately noticed that the brake pedal was extremely soft and wouldn't build up pressure. Not to mention sticky steering wheel and grease on the carpet. So I had to take a couple hours of sick leave this morning to take the truck back. They called an hour ago and said there is absolutely nothing wrong with my brakes and all the trucks on the lot have the same soft pedal. It will be tomorrow morning before I can pick it up (again).

 

At this point I don't know what to do. The pedal had a good firm feel when I dropped it off now it has almost no pressure but the dealer insists its right.

Posted

Mine has been clunking and really is bad!!I have 7000 miles on it and it is kept in garage.

 

Jimmy W,

 

We're sorry to learn you're experiencing clunking issues with your vehicle. Have you had your vehicle into the dealership? We'd like to discuss this further with you. If you are interested, please send me a private message here on the site with your full contact information, VIN, mileage and dealership name.

 

Thank you,

 

Andraya

GM Customer Care

Posted

My pedal had a good solid feel before the dealer replaced the EBCM. They looked at it again and said the pedal was normal and was the same as others on the lot. Again I can't stress enough that my pedal was way softer after the dealer replaced the EBCM. After doing some research on the web I found out that the module can trap air in it and needs to be bled with a special scan tool or get the ABS to activate.

 

So....it's raining here tonight so I went out and slammed the brakes about a dozen time to activate the ABS and presto. Pedal is noticeably firmer. Call BS if you want but that's my story.

 

As far as the clanking, it very sporadic and my guess is the slip yoke. The vibration is also sporadic but i had a 2015 Tahoe as a rental and I noticed the same vibration when it went into V4 mode and I had a light load but not quit enough to go back to 8 cylinders.

  • Like 1
Posted

My pedal had a good solid feel before the dealer replaced the EBCM. They looked at it again and said the pedal was normal and was the same as others on the lot. Again I can't stress enough that my pedal was way softer after the dealer replaced the EBCM. After doing some research on the web I found out that the module can trap air in it and needs to be bled with a special scan tool or get the ABS to activate.

 

So....it's raining here tonight so I went out and slammed the brakes about a dozen time to activate the ABS and presto. Pedal is noticeably firmer. Call BS if you want but that's my story.

 

As far as the clanking, it very sporadic and my guess is the slip yoke. The vibration is also sporadic but i had a 2015 Tahoe as a rental and I noticed the same vibration when it went into V4 mode and I had a light load but not quit enough to go back to 8 cylinders.

Sounds like my 02 lol. Bad slip yoke and bad straps on the U joint.

Posted

Just to clarify I did bleed the brakes at each wheel also. Pedal is a lot better. Not sure why the stealer insisted it was fine.

Posted

This question is for Andraya of GM customer care. Will GM honor my drivetrain warranty after 100,000 miles if I document my issue now with 14000? GM is saying it is normal but we all know something is going to break eventually.

Posted

I'm having the exact same problem. Most noticeable when applying gas after the truck has been coasting for a second.

 

The "Clunk" or "Thud" is becoming more and more noticeable and feels like bad u-joints to me.

 

A trip to the dealer is the last thing I have time for at the moment. :(

Posted

My noise is exactly how LS 1st GEN describes. I'd make time for the trip to the dealer. They'll probably say they can't reproduce it but at least it'll be documented.

  • Like 1
Posted

I just bought a 2014 sierra 1500 4.3/v6 reg cab/reg bed.

has less than 500 miles on it and ....

I am getting the exact same sound!! I,too, took the mechanic with me to duplicate the noise. it sounds just like a defective u joint!! on acceleration and deceleration. also... when coasting down a hill I get the repeating knocking noise.

they did not tell me it is normall, but, rather kept the truck for 2 days until the gmc tech rep showed up. it has been identified as a faulty baffle in the muffler/exhaust system. a new muffler /exhaust system is on order and being installed next week.

the tech rep. told us there is a bulletin out on this issue for 2014 sierra's.

after I get the new muffler installed..... will let you know the outcome.

>>>although the gmc technical representative identified the noise as a muffler/exhaust issue.... I still think it's connected to the u joint/drive shaft area.

the mechanic told me they had some 2014 sierra's sl's that needed to have the driveshaft/u joints replaced and noise went away.

Posted

I just bought a 2014 sierra 1500 4.3/v6 reg cab/reg bed.

has less than 500 miles on it and ....

I am getting the exact same sound!! I,too, took the mechanic with me to duplicate the noise. it sounds just like a defective u joint!! on acceleration and deceleration. also... when coasting down a hill I get the repeating knocking noise.

they did not tell me it is normall, but, rather kept the truck for 2 days until the gmc tech rep showed up. it has been identified as a faulty baffle in the muffler/exhaust system. a new muffler /exhaust system is on order and being installed next week.

the tech rep. told us there is a bulletin out on this issue for 2014 sierra's.

after I get the new muffler installed..... will let you know the outcome.

>>>although the gmc technical representative identified the noise as a muffler/exhaust issue.... I still think it's connected to the u joint/drive shaft area.

the mechanic told me they had some 2014 sierra's sl's that needed to have the driveshaft/u joints replaced and noise went away.

  • 2 weeks later...
Posted (edited)

First time poster - but had to voice my concern with the dreaded clunking sound as well.

 

I just crossed 5,000 miles on my 2014 Sierra SLT 5.3 V8 and have been having the "clunking" noise happen as well (been going on for a little over a month/month .5 - I thought I was crazy the first couple of weeks hearing the noise), but it is only when accelerating (I'm probably missing it when coming to a stop to be honest) and it does not happen every time I drive. Only sporadically. It sounds like the bed is about to fall off - that's how loud/unruly the clunking sounds.

 

I took it in to be looked at two weeks ago and the service rep actually heard it when another rep was driving it out of the loading/unloading area of the service area so I know I was not crazy (he told me that we could not readily drive it around since it was raining but I felt that since he heard it - my point was made). Got it back a day later and had not heard anything of it. However, I finally heard the dreaded clunking noise again yesterday afternoon and then again this morning while driving to work.

Very frustrating because they actually told me that it was a problem in the bumper area and had sent it to 'the shop' to get fixed. What? So something else was wrong with the truck or BS excuse?

 

I've already had a hard enough time with them about getting the rear left seat rattle looked at. First time they could not replicate the noise. Second time they said it was the "loose" jack kit under the seat (when I know good and well it was the seat itself because once you hold it down or sit on it the rattle goes away). I eventually had to take the advice of a thread on this forum (I believe it was this forum) and slam the seat down five times and ending up fixing that problem myself. This was even after reading off responses to the service rep from that very thread about the issue!

Edited by ashmores
Posted

Hey ashmores,

 

We're sorry to hear you're experiencing a similar clunking noise in your Silverado. We'd be happy to contact the dealer on your behalf and look into this further. Feel free to send us a PM with you full contact information, VIN, mileage, and involved dealer if interested. If you're unable to send a PM due to just joining the forum, we can also be reached via email at [email protected].

 

Sincerely,

 

Eddie A.

GM Customer Care

Posted

First time poster - but had to voice my concern with the dreaded clunking sound as well.

 

I just crossed 5,000 miles on my 2014 Sierra SLT 5.3 V8 and have been having the "clunking" noise happen as well (been going on for a little over a month/month .5 - I thought I was crazy the first couple of weeks hearing the noise), but it is only when accelerating (I'm probably missing it when coming to a stop to be honest) and it does not happen every time I drive. Only sporadically. It sounds like the bed is about to fall off - that's how loud/unruly the clunking sounds.

 

I took it in to be looked at two weeks ago and the service rep actually heard it when another rep was driving it out of the loading/unloading area of the service area so I know I was not crazy (he told me that we could not readily drive it around since it was raining but I felt that since he heard it - my point was made). Got it back a day later and had not heard anything of it. However, I finally heard the dreaded clunking noise again yesterday afternoon and then again this morning while driving to work.

 

Very frustrating because they actually told me that it was a problem in the bumper area and had sent it to 'the shop' to get fixed. What? So something else was wrong with the truck or BS excuse?

 

I've already had a hard enough time with them about getting the rear left seat rattle looked at. First time they could not replicate the noise. Second time they said it was the "loose" jack kit under the seat (when I know good and well it was the seat itself because once you hold it down or sit on it the rattle goes away). I eventually had to take the advice of a thread on this forum (I believe it was this forum) and slam the seat down five times and ending up fixing that problem myself. This was even after reading off responses to the service rep from that very thread about the issue!

 

I've had the 'clunk' since day one, i've been to two different dealers and both of them heard the noise. one said it's normal and the other one literally blamed it on my trailer hitch haha. i took the hitch off and the sound was still there and the mechanic wouldn't change his diagnosis, said it was the trailer hitch (which was no longer even attached to the truck). Needless to say, that dealership is a bunch of idiots and i told the service manager that.

 

i hope someone figures out the 'clunk' but im hoping that whatever is causing the sound gets so bad that something clearly fails or breaks so that i can just rub it in both the dealers faces/have it replaced.

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

    • Can it still be Assembled I?    Stribeck says that we need a certain amount of viscosity under conditions of load and velocity to prevent two surfaces of a know roughness from tearing each other asunder. And we have marketing trying to tell the masses that those two surfaced require less of that commodity due to more exact limits being placed on the same old clearances. We also know that there are limits to how hard something can before it becomes to brittle to be viable and to smooth to 'wet' the surface and that both of those conditions have been known and met since about the Second World War.    That viscosity value shook out at 10 centistokes at 212 F just under a hundred years ago.  Give this a look: [Anton Parr]     What is advertised is the Kinematic viscosity (mm2/s) or that which has been density adjusted but the value we are after is the dynamic viscosity (mPa.s) or true viscosity. You can see that this number is dependent on density thus base stock and temperature. You can also see that an SAE 30 doesn't reach that value in this example. However an SAE 30 that is at the upper end of the SAE 30 range; 12.5 cSt (mm2/s), might. 12.5 * .83 = 10.375 (mm2/s). If you could find an SAE 30 at the upper end these days.   Then there is the complication of viscosity modifiers or VII or VM, whatever you wish to call them. Polymers added to very thin base oils, perhaps 3 to 6 cP oils, that will meet the SAE *W30 spec at 'tested' shear rates and 100 C/212F  target temperature. So a polymer fortified base that is a fraction of the 10 cP requirement Stribeck insist upon.   This could be all well and good if those polymers didn't have two very problematic 'features'. They shear or loose viscosity both 1.) permanently and 2.) temporality. And they do both omitted in the advertised data with the distinct  purpose of deceiving the consumer of the actual operating state of the fluid. I've shown the example of Warren Oils COSTCO 10.91 cSt 5W30 formuation several times where the 100 C HTHS value is 6.9 cP!! That's the temporary shear down and with and SSI or shear stability index of 9.4 cSt. Note the intentional deception in using mixed units?    After a short while that 9.4 cSt oil has a viscosity corrected dynamic value of 7.8 cP. But as the SSI is still within the range of an SAE *W30 whose lower value is 9.3 cSt.    This allows them to continue to call this SAE 16 weight oil a 30 weight, the cake, and still meet the API requirements for fuel efficiency IMPROVEMENT mandated by the EPA. The eating of the cake. By the time you've worn out your motor doing the responsible thing by adhering to the warranty requirements, (the stick), you get deprived of the carrot, wear control. So sad, to bad.   So what can be done? Do I need actually say? [Anton Parr]       Even this must be monitored if the oil is on the low side and the VII an organic or you opt for a 0W40 with an even lighter base oil and more / higher MW VII. (Note the lower density of the 40 weight versus the SAE 30 mono-weight?)    There is another workaround. Temperature. An SAE *W30 run at a bulk temperature of between 180 and 195 F.    Being the belt and suspenders sort I am I do both. Run it cook and run it heavy.    In Part II I'll work the AW package. 
    • So, do I go elbow-deep on this thing or list it for sale and play dumb? Seems to "runs good."   I'm about $1200 away from having: -a rebuilt injector ($300) -a new cat ($250) -a new cat back exhaust (OE style) ($300) -a new AC compressor ($200) -AC refrigerant charge ($150)   In theory, this should rectify the obvious detracting issues from its value and operability. Cold AC with a non-squeaking AC pulley both sounds and feels good. An exhaust that isn't cut/hacked in 17 different places and doesn't vibrate on a crossmember would make it sound and feel less janky. A working cat would help the stink, and will save the earth, but *if and only if* the fuel system is working properly, which would also address the intermittent "rich" CEL.   Heard a good one... CEL for "Rich condition" means you haven't spent enough money on the truck lately, and it's letting you know.   Rebuilding the injector would seem to be the most important part. Replacing the cat would be secondary. I don't think mine is plugged or overly restricted, but it might be a little restricted? I have no good way to tell other than seat of the pants feel. I hate the smell.   The current theory is I have a rich idle problem: A bad fuel pressure regulator, or a leaking injector(s) being the highest probabilities. I already replaced the FPR but that doesn't mean its replacement isn't also bad. It was a new part from Dorman, but the packaging looked like it had been sitting on a shelf for 20 years.   This is the (single) upstream O2 sensor shown at idle. I'm getting a lot of "rich" it seems. Sometimes it stays high like that and doesn't drop down. That makes me think it's processing injector leaks or a partially stuck open injector.     Other times it looks like this. Nice oscillations between rich and lean, which is what I think it should be. Under load and at speed, the oscillations are nice and tight and uniform looking, high and low.     Fuel trims suggest the PCM is compensating pretty hard at idle to pull fuel out. But it's not enough to trip a CEL. Something about slowing to a stop: brake vaccum booster, EGR, or the EVAP purge is delayed, or there's pooled fuel in the intake again that's draining into a cylinder is enough to set the CEL. Of course, in two days of driving, it hasn't set. I was hoping to actually look at the freeze-frame data when it sets. IAT is high because it's idling on an 83 degree day here.  
    • 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.      
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...