2006 Sierra CC Z-71

ENIGMA206 · September 25, 2006

I have a 2006 Sierra 1500 Crew Cab Z-71, 5.3 litre with 13,000 miles. At about 5,000 miles I started hearing a low frequency oscillating sound around 55 to 57 MPH as I was coming off of the highway. As time went on, I started picking up the noise at a slower frequency as low as 35 MPH. It finally had worked its way to making the noise from 35 to 75 MPH. A friend who is a former ASE mechanic convinced me it was the stock tires. I couldn't take the sound anymore so I went and dropped 800 clams on new Revos. Well, guess what? The noise is still there. Nothing changed at all. So anyhow, last week I was going down the interstate with a buddy and he mentioned the sound. Just for kicks, I engaged 4-Hi. The noise went away immediately. Once disengaged from 4-Hi, it would take about 1 to 2 minutes before the sound would come back. I did this about 7 or 8 times with the same results. When I got home, I checked the fluids in the tranny, transfer case and front differential. All was good. I will be taking it to the dealer this week if I can get in, but would like to hear some other opinions as to what it might be. I will be taking a 20 hour road trip next month and surely don't want to listen to this thing for that long, plus not be able to count on its reliability. And by the way, turning up the stereo doesn't help.

motorhead1996 · September 28, 2006

I'm curious to hear what you find out. It sounds similar to a noise that I have heard on my truck. Please post back.

OchAyeZ71 · September 29, 2006

I believe I have a similar symptom. Mine has a low frequency front end noise/vibration that oscillates depending on my speed. It appears to occur at freeway speeds only. It sounds like the noise you would get from a tire rubbing, but my tires/wheels are stock. I was going to change the front diff fluid since I just had the rear diff, xfer case, and xmission done (50k service). I have new Michelin LTX.

I do not have a warranty so I am interested in what you found out from GM.

pm26 · September 29, 2006

I do not have a warranty so I am interested in what you found out from GM.

<{POST_SNAPBACK}>

It will be the standard replies:

"CANNOT DUPLICATE"

"NORMAL FOR THIS VEHICLE"

"NO SERVICE BULLETIN ON THIS ISSUE"

"NO ABNORMAL NOISES HEARD DURING TEST DRIVE"

OchAyeZ71 · October 2, 2006

I found another post similar to this. It mentioned something called Frame Beaming. It sounded like some harmonic in the frame that did not appear to have a immediate cure. The test was to put 300lbs of stuff in the bed behind the axel. If the noise went away it was FB.

One thing to note when I bought mine a couple of months ago it had the original Bridgestones on it at 49k mi. I drove it about 30mi on the freeway to Cosco for some new Michelins. I did not notice the oscillating vibration with the old tires for that drive. I only noticed it with the new tires. Again mine is subtle and almost undetectible with the stereo on so it might have been present.

My thoughts; wheel bearing, drive shaft, heat shield???

GM-Tech · October 2, 2006

Frame beaming causes a vibration not a noise.

ENIGMA206 · October 2, 2006

Well, just as I thought, the technician took my truck for a test ride and didn't hear what I was hearing. When I went to pick the truck up, he volunteered to take a ride with me. I told him riding around town wouldn't do, so we headed out to I-95. Within 30 seconds it was making the noise and he crawled all over the cab trying to isolate the sound, but couldn't find a source other than me saying it felt as if it were coming from under my left foot on the floor board.

When we got back to the shop, the tech found a TSB (sorry, but I don't have the number with me) for the exact same symptoms. The description was identical: oscillating frequency from 30 to 70 MPH, goes away when locked in 4-Hi or Auto 4. The cause is supposed to be the ring gear on the left side of the front transaxle is out of tolerance. Once at a sustained speed when 4WD is disengaged, the spinning of the front axles is supposedly causing enough turbulance to get the inner workings of the front transaxle moving.

The tech replaced the left ring gear, bearings, shims and retaining ring. The repair definately made a difference. The sound is still there, but barely audible. It also changed in frequency. The oscillations are much slower now. I'm wanting to wait a while to see if it gets better or worse as things settle in.

I will look on my paperwork to see if the TSB number is there. Hope this helps. Hopefully my terminology is correct.

OchAyeZ71 · October 4, 2006

This is great information. It sounds like we have the same or similar issue now. Please send out the TSB# when you get a chance. I would like to find out what this would cost w/o warranty. I wonder what else in the front drive train could contribute to the noise. I will have to try Auto 4WD on the freeway to see if it goes away. Whatever it is it does not appear to affect the gas mileage.

GM-Tech, any ideas?? Thanks.

ENIGMA206 · October 4, 2006

Just a follow-up to let those interested know what's happeing. My tech called me Monday to see how the repair is doing. I told him about the slight harmonic still present. He called the factory tech help line to see if there was a follow-up procedure if the repair wasn't 100%. When the tech did the repair, he removed the ring gear and other parts without removing the transaxle or differential. He was told that aligning the differential was another part of the repair. He was also told to break loose the carrier bolts on the front end while lifted, then raise and lower the truck several times so everything finds a static position, then re-tighten. I'll be taking it in tomorrow morning for this and will try to remember to get the TSB# while there.