Things Go Thump Thump Thump

[fyrman]

Anyone have a thump thump thump sound coming from the front tire. My 2014 Z71 Sierra has this noise at about 60 to 65 mph and does not matter on what type of roadway surface. My wife says she can feel it a little I do not feel it but hear it. It appears to be from the front driver tire. I am not a fan of the Goodyears, but think it sounds like a wheel bearing going bad. 400 miles. It is at the dealership they have never heard this noise. they tell me.

[fondupot]

Could be a tire out of balance, or a tire out of round. It happens.

 

Good luck getting it figured out. Let us know what you find out.

[newdude]

Tire or brake? Bad wheel bearing would make a hum or growl.

[fyrman]

Dealership has a call into GM Tech to help with the problem. I will pass on this information tot he dealership. Keep the ideas coming.

[newdude]

Does the dealer have a guy whos good with NVH (Noise Vibration Harshness)? They should be able to do a vibration analysis on the truck with the GM vibration analyzer at the speeds the problem occurs at. If you have to ride with them to get it to duplicate if they can't duplicate it do that as well.

 

There is also a tire bulletin on the new trucks as well: #13-03-10-002

[pm26]

What size are these tires? Sounds like a bad tire to me. Jack up the truck and spin the whee/tire by hand and see if there is waviness in the thread, indicating a broken belt.

 

It can also be a bad hub, such as bearing pressed in incorrectly.

[fondupot]

Does the dealer have a guy whos good with NVH (Noise Vibration Harshness)? They should be able to do a vibration analysis on the truck with the GM vibration analyzer at the speeds the problem occurs at. If you have to ride with them to get it to duplicate if they can't duplicate it do that as well.

 

There is also a tire bulletin on the new trucks as well: #13-03-10-002

 

Can you get us more info on the bulletin?

[fyrman]

The tires are the 20 inch Goodyears 265/55.

[fyrman]

The dealer was able to duplicate the thump. They just have never had it before.

[1kwik72]

Can you get us more info on the bulletin?

I just looked it up, nothing earth shattering. It is a pretty long bulletin that outlines step by step procedures for balancing (road force variation) along with various worksheets relating to vibration analysis and documentation before contacting TAC. Basically it walks the dealers through all the bases and has them record the proper information so that TAC can make a recommendation. My guess is that if the tech systematically goes through all the steps they will 9 times out of 10 find the issue, if not they will have sufficient info that GM engineering will have the info they need to identify where the issue lies.

 

Craig

[fondupot]

I just looked it up, nothing earth shattering. It is a pretty long bulletin that outlines step by step procedures for balancing (road force variation) along with various worksheets relating to vibration analysis and documentation before contacting TAC. Basically it walks the dealers through all the bases and has them record the proper information so that TAC can make a recommendation. My guess is that if the tech systematically goes through all the steps they will 9 times out of 10 find the issue, if not they will have sufficient info that GM engineering will have the info they need to identify where the issue lies.

 

Craig

 

Gotcha, Ok. Reason I ask is I put some real highway miles on the truck over the weekend. And got up to speeds around 80-85 for short times and felt like I may have had a tire out of balance out back.

[fyrman]

Just left the dealership. On arrival I see my truck up on the lift and the front differential on the bench. I am told a bearing is bad in the differential. The bearing has become damaged to the point it can not be removed from the housing so GM is sending a complete new assembled unit to bolt in place of the bad. I was told the GM tech's have had a few reports of this so far.

[GMCustomerService]

Thanks for the update, fyrman! Keep us updated along the way, and if you feel you need any additional support we're here.

 

Regards,

 

Sarah (Assisting Jennifer)

GM Customer Care

[fyrman]

We'll things have not gotten better today. I go to check update on repairs and find truck back together with old differential. I am told may take 30 days to get parts but think it will be ok to drive until then. I go talk to dealership owner who is a great guy and he calls GM rep and is told a new differential will be built in 5 days and shipped for another 5 days and the installed. I do not feel secure driving this truck in this condition and worry we may do even more damage to the drivetrain. So am I mad no,am I disappointed, yes . 400 miles on a beautiful looking truck I can not use or feel secure using until the repairs are completed. We'll at least I have not made the first payment.

[fondupot]

Stinks to hear about the differential.

 

Tell em to keep the truck and give you a loaner. I would agree, if you don't feel safe driving it. Make them give you a loaner and drive that until your truck is fixed.