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Vibration in Auto 4WD mode from 40-50 mph

SierraMyst

By SierraMyst
in Troubleshooting & Recalls

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SierraMyst Enthusiast

SierraMyst

Posted
Posted

I've been looking and haven't found any similar thread.

 

My 2016 A/T truck is very smooth across the board at all speeds in 2WD mode.

 

So we had the blizzard here in the northeast last week and as the snow has been melting and refreezing, I've been driving in Auto mode.

 

I've started noticing that if I give it medium to heavy throttle, the truck vibrates from 40-50 mph.

 

It's smooth up to to 39 mph, and smooth once I'm up to normal speeds of 65-75 mph.

 

It only happens from 40-50 mph and in Auto 4WD. And never on slow acceleration such as traffic light to traffic light.

 

Anyone else have this? Is this normal?

pm26 Senior Enthusiast

pm26

Posted
Posted (edited)

Snow frozen in the wheel

More likely poorly assembled cheap parts.

Edited by pm26
Ionize New Member

Ionize

Posted
Posted

My '15 DC V6 6-spd does the same thing...in auto 4WD only, it has alot more harmonic vibration in the gas pedal/wheel.

No sign of it in 2WD. This is on dry payment, warm temps, no traction issues, only light/part throttle. It seems to do it from a lower speed, approx.

10-15 mph, then slowly fades as speed increases. Not sure if it does it in regular 4WD, will check.

fondupot Senior Enthusiast

fondupot

Posted
Posted (edited)

no need to be driving in 4 auto at that speed anyway. the transfer case is meant to shift on the fly.

 

use it to get traction on start-offs. But turn it back to 2wheel once you are above 30mph.

 

No 4 wheel drive system is going to keep you from slipping when at higher speeds

Edited by fondupot
  • Like 1
redwngr Senior Enthusiast

redwngr

Posted
Posted

Is the Auto engaging/disengaging the transfer case when you 'push it' at those speeds?

 

Does it also vibrate under those conditions in 4H?

SierraMyst Enthusiast

SierraMyst

Posted
  • Author
Posted

I'd check your front driveshaft to see if it's balanced.

Is that something I can do or the dealer?

fondupot Senior Enthusiast

fondupot

Posted
Posted (edited)

Is that something I can do or the dealer?

 

Do you have a driveshaft balancing machine in your garage?

 

No?

 

In that case....take it to the dealer.

Edited by fondupot
SierraMyst Enthusiast

SierraMyst

Posted
  • Author
Posted

Is the Auto engaging/disengaging the transfer case when you 'push it' at those speeds?

 

Does it also vibrate under those conditions in 4H?

So it does it in 4H too. So it's definitely a transfer case related issue.

 

I'll have the dealer look it. Since no one else is experiencing slight vibrations with 4WD engaged.

 

Kind of odd, since I have no vibrations with my truck at all (except AFM related stuff) in 2WD. I can cruise at all speeds and it's butter smooth. No wheel/tire issues.

 

I'm kind of surprised no one else have any kind of slight vibrations with 4WD engaged.

 

I guess the plus side is that I dont really drive in 4WD very often.

  • 4 weeks later...
SierraMyst Enthusiast

SierraMyst

Posted
  • Author
Posted (edited)

The truck was flawless in 2wd mode. 2 weeks ago.

 

I left instructions on how to duplicate it the shake. I stopped by the dealership the day before I left town so I could ride with the tech. They said they didn't need me to.

 

I came back two weeks later only to find out that they balanced my wheels unnecessarily.

 

There were no vibration issues in 2wd.

 

They said that all 4 of my wheels were 1 ounce off and balanced them for me. I asked them if they could still feel the vibration after the balancing and you know what they said...

 

"We couldn't duplicate the vibration before, so there was nothing compare it to after"

 

WTF....?

 

You didn't test drive the truck before?

 

You just randomly balanced tires that didn't need balancing?

 

The truck drove different in 2wd vs 4wd and not a single damn tech was able to drive it in both modes (auto and 2wd) and tell the difference?

 

Now my truck vibrates on the highway at 75 mph. Which it didn't before. I didn't give a crap if the wheels were out of spec, it didn't shake in 2wd. And it still shakes in Auto mode.

 

Oh...they also recommend I don't drive in Auto on dry pavement. Something I never do.

 

It didnt shale before. Now it does...thanks GMC. If your reading this, your techs are completely incompetent.

 

I am so mad...I must be going to the most circus of a dealership in my region.

 

I walked over to the sales floor and test drove 2 other trucks....guess what. Auto mode from 40-50 mph....smooth.

 

Bet they didn't do that either.

 

God forbid they drive another truck and see of if the issue is common. Oh wait. They drive the truck. They just guessed the issue was a balance.

 

Because that's what GMC professional grade technicians do, guess at repairs.

Edited by SierraMyst
  • 2 years later...
Bknowles82 New Member

Bknowles82

Posted
Posted

I've started noticing the same issues with my 15 Silverado. When I first purchased it, All of my driving was in Auto. Now once I get up to around the 50mph mark I get a very evident vibration. I switch it to 2wd and the vibration goes away. Has anyone gotten a resolution for this?

  • 1 year later...
  • 11 months later...

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