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2014 Silverattle

madical1

By madical1
in Ask A GM Technician

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madical1 Enthusiast

madical1

Posted
Posted

Brand new WT2 vibrates at speed. I feel it mainly in the steering wheel, passengers feel it in the seat. After engaging gears, drive seems to slip and then grabs with a clunk. The engine idles very rough. Took veh to dealership, tech said no codes and fluids fine. Cashier gave me 1 page paper and said I need to speak with service specialist who coincidentally was no where to be found. Had to go to work so I just left. Took veh on 200 mile trip again, no change, very uncomfortable. Could this be a Lemon? Any suggestions?

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

You don't say how many miles on the truck. Also don't know what engine, or 2wd or 4wd. You need to make sure everyone involved knows that not everything is controlled by the pcm/ecm/tcm/bcm. Just because there is no code, does not mean there is no issue. All that means is that now the technician has to return to being "just a mechanic".

 

If you can reproduce the issues you have reliably, then show the service manager what it is you are complaining about. If they insist it is normal, then ask them to show you a truck on the lot doing it. Any time you get the "its normal" result from service department, check the same model vehicle on the lot.

 

Sometimes when you buy a brand new vehicle, you find that it is doing something foreign to you. Your brain says it is broken, but, it is more likely going to be "just different" to what you expect. I remember when I first drove my 98 GTP, it was just off the transport(happened to be there when it came in), the dealer put the dealer plate on it, and off I went. Having not driven an automatic car in years(and also 8 years out of trade) and noticed right away that something odd was going on with the shift to what I thought was high gear. When I was done my test drive I told the salesman to have the transmission looked at, it was not shifting right. Turns out is was shifting normally, I never expected a transmission to lock up the converter in 3rd and 4th gear.

madical1 Enthusiast

madical1

Posted
  • Author
Posted

Thank you for the reply. If I may elaborate. 2014 Silverado Work Truck. 2 WD, 6 Cyl. 3k miles. I've driven the vehicle on 3 long trips, and use it to commute to work 50 miles round trip each day. The steering wheel receives what can best be described as a pulsing vibration which then goes away and then comes back. At 70 MPH it becomes more constant and of longer duration. I have video of a water bottle shaking all over the place. The vibration at idle is annoying because it's something I've never experienced, not even on my my older cars. It's more annoying at stop lights. I think the clunking when engaging gears is maybe related to the very low idle. The dealership experience wasn't a very good one. i'll make sure that I'm more assertive at my next appointment. Video on youtube.....

 

 

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

That looks more like a driveline vibration or tire vibration(not balance, more like tread pattern). What air pressures are you running in the tires? Use a gauge that you trust over the sensors for TPMS. If you pop the truck into neutral does the vibration stay? The new V6 engine is a new engine design that only shares displacement with the previous 4.3l engine, and is based on the GenV LT1 engine.

 

Is that sound in the first couple of videos rain? Seems overly loud in the cab of the truck for just rain. Almost sounds like hail or small stones.

 

A bit off topic but, how do you find the power of the V6? I know they advertise some high numbers, but those are not the conditions you drive at. Why they can't just list what torque is needed to pull a trailer up a hill, and with the V6 can it produce that amount of torque without the need of dropping down 2 gears and be running at 4800rpm by the time you crest the hill.

madical1 Enthusiast

madical1

Posted
  • Author
Posted

It was raining. Maybe the IPhone just picked up those sounds above everything else. I'll check the air with a new guage tomorrow. I havent towed anything, the speed is fine, I've 100 hours and 3k miles, 21 MPG. I've just uploaded a video of the rough idle. I found a video of a normal idle (?), and compared to mine. The camera phone doesnt have the speed to capture the shake, the dip stick shakes so hard you can't read the insignia on the end.

white1500 Senior Enthusiast

white1500

Posted
Posted

I'm assuming that you're on Goodyear's? If so, there your problem. Replace with quality tires at 35 psi cold and check back. :)

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

Tires are 39 PSI all around.

 

What is the suggested pressure supposed to be for your truck? If it was me, I would drop the pressure to 30psi, then see if there is any change. If there is a change, then it is likely an aggressive tread and high pressure causing it. Set pressures to the low number of the suggested range in your manual.

After this test, return the air pressure back to suggested pressures. Do not keep driving it with low pressures, or you will get to experience what the Ford/Firestone combo experienced.

madical1 Enthusiast

madical1

Posted
  • Author
Posted
I'm assuming that you're on Goodyear's? If so, there your problem. Replace with quality tires at 35 psi cold and check back. :)[/quote

 

Bridgestone Dueler H/T 684 ||, 255/70R17

madical1 Enthusiast

madical1

Posted
  • Author
Posted

What is the suggested pressure supposed to be for your truck? If it was me, I would drop the pressure to 30psi, then see if there is any change. If there is a change, then it is likely an aggressive tread and high pressure causing it. Set pressures to the low number of the suggested range in your manual.

After this test, return the air pressure back to suggested pressures. Do not keep driving it with low pressures, or you will get to experience what the Ford/Firestone combo experienced.

Lowered pressure to 35 all around. Same experience. Checked max PSI from door and found to be max 35. I'll set to 30 in the morning and drive to work, see how it responds.

madical1 Enthusiast

madical1

Posted
  • Author
Posted

I'm assuming that you're on Goodyear's? If so, there your problem. Replace with quality tires at 35 psi cold and check back. :)

Bridgestone Dueler H/T 684 ||, 255/70R17

  • 3 weeks later...
madical1 Enthusiast

madical1

Posted
  • Author
Posted

OK, so I took vehicle in to the dealership. Left it there for the day. Told them i wanted them to drive the car on the interstate toll road ( newly paved). Had a toll pass in the truck so no cost to them. They told me nothing is wrong. Suggested I throw in 300lbs of sandbags in the back. Said the problem with the shake and the rough idle is the active fuel management system. It's performing as it should. Huge thunderstorm, couldnt make them show me another vehicle that performs this way. Gordon Chevrolet, Tampa.

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

AFM doesn't activate at idle or any other low speeds to prevent rough running.

 

The weight suggestion is just absurd. Escalate this at the dealer or find a new one cause they're talking out of their backsides.

  • 3 weeks later...
madical1 Enthusiast

madical1

Posted
  • Author
Posted

That looks more like a driveline vibration or tire vibration(not balance, more like tread pattern). What air pressures are you running in the tires? Use a gauge that you trust over the sensors for TPMS. If you pop the truck into neutral does the vibration stay? The new V6 engine is a new engine design that only shares displacement with the previous 4.3l engine, and is based on the GenV LT1 engine.

 

Is that sound in the first couple of videos rain? Seems overly loud in the cab of the truck for just rain. Almost sounds like hail or small stones.

 

A bit off topic but, how do you find the power of the V6? I know they advertise some high numbers, but those are not the conditions you drive at. Why they can't just list what torque is needed to pull a trailer up a hill, and with the V6 can it produce that amount of torque without the need of dropping down 2 gears and be running at 4800rpm by the time you crest the hill.

That looks more like a driveline vibration or tire vibration(not balance, more like tread pattern). What air pressures are you running in the tires? Use a gauge that you trust over the sensors for TPMS. If you pop the truck into neutral does the vibration stay? The new V6 engine is a new engine design that only shares displacement with the previous 4.3l engine, and is based on the GenV LT1 engine.

 

Is that sound in the first couple of videos rain? Seems overly loud in the cab of the truck for just rain. Almost sounds like hail or small stones.

 

A bit off topic but, how do you find the power of the V6? I know they advertise some high numbers, but those are not the conditions you drive at. Why they can't just list what torque is needed to pull a trailer up a hill, and with the V6 can it produce that amount of torque without the need of dropping down 2 gears and be running at 4800rpm by the time you crest the hill.

Here's the email frm the dealership

 

 

I am sorry you are having issues with your vehicle, and also that you feel our answers absurd. However, these conditions have been evaluated and verified and are considered normal operating characteristics. Simply put we can demonstrate the same conditions on other similarly equipped vehicles. Therefore no repair attempts are made as these are engineering issues not repair issues. If GM decides these conditions are repairable and provides instructions we will be happy to follow any process to accommodate repair. This vehicle was evaluated by me, and my shop foreman, and compared to other 6 cylinder vehicles here. We also spoke to GM technical assistance who advised us that these vibrations are considered normal.

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

I would take them up on the offer to demonstrate other similar vehicles operating the same way. Do not wait too long, they will just say that they sold all the trucks like yours if you wait too long.

 

Who wrote this email to you?

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