Strake

trust me...... Chevy know about it. My YouTube video / audio was sent to Mary Barra the CEO of GM. I got a phone call a day later. The Corvette brand quality Mgr is WELL aware of this.

GM Engineering bought my car back, after sending one of their Lead Development Engineers for noise and vibration to my local dealer and collected another 2 days of data with over 30 sensors connected to just about everything in the drivetrain, and suspension components. My car went back to Detroit mid Nov for a total tear down and analysis of the components. It looks like it's in the differential. No surprise to me, as that is the component that is different between the Stingray, Z51, GS and of course the Z06.

Highplains

I had exactly the same experience as Richard only I opted for a repair rather than a buy-back-at least until I'm satisfied that the new diff will work.

Strake

They used our car as the one to determine for certain what the issue is. They also had a couple of other data points too.

The Engineer who came to Gettysburg had already spent 2 weeks doing sound analysis on my video/ audio clip that was posted, and sent to GM Exec offices. He showed me some of the data which sliced and diced the sound bites into great detail and isolation.

With that said, they already had a head start on my car. It was the right choice to sent it to Detroit on a buy back to get to the root cause for the overall problem

As a side note, the last drive to the dealership to make the buyback/trade was about 5 weeks after the decision was made to do this, and they had me factory order a replacement car. The WARBLE was noticeably worse for the 8 mile drive to the local dealership. I had been asked NOT to drive the car during the time that we made the deal and the time that the actual trade took place. Same as what Pete was seeing with his.

Gunrun

Looks like we are still at stage 1 lol. I wonder how many owners don't even know of the warble noise.

Highplains

Not everyone has to jump all the hoops that Richard, myself and Bruce Jones did. At this point, its a matter of waiting for a bulletin or recall to go into effect. In the meantime, if you have the noise, your dealer can call the Technical Assistance Center for instructions. I've got what they think is the fix for the problem installed now and am waiting to see if it will work.

Gunrun

Do you have a part number yet? If this is the fix I will get it done asap with my first oil change. Hell I might even bring it to your dealer Highplains. Which shop in Kansas. I have family in Atchison. About 1 hour from me in Missouri. Thanks.

IBuyGuyToys

Waiting for formal announcement as I’m going to have to wait until the weather warms up anyway, temps been single digit here in northeast Ohio and chevy in their infinite wisdom didn’t give us a tire choice.
Had problem since December 9, 2015, another month isn’t going to matter.
Also think the director of service at dealership has disowned me because I opened a case with Chevy Customer Care to gain more exposure.

Highplains

I don't have a part number and as near as I can tell, there isn't one on the job order. The diff that was put into my car was taken directly off of the assembly line by the Corvette Quality Control Manager and shipped to my dealer in Wichita, Kansas. At that point, we found an appointment time that would coordinate with a field engineer who took sound readings from the car before and after the install which he supervised. Although I have been told that this is the big fix, I'm sure Detroit is still using this as a test case. My old diff goes back to Detroit for tear down.

I was told that in advance of a TSB or recall being issued that an owner can go to his dealer about the problem. If the dealer doesn't have a clue (and it seems most don't) to have him call the Technical Assistance Center and they would receive directions on what to do. That's all I know to tell you and I've repeated it several times in previous posts

ndmo

Since you have been paying attention to this longer than I.. I have a z51, and have a similar but more metallic sound along with rear diff chatter and some other issues within the drive train. Chevy told me they were aware of the rear diff chatter and some of the sounds. But as I have been reading this, it seems I am alone on the z51 having this problem. Does that seem to be the consensus?

Highplains

Yours may be the second Z51 I've heard of. Does the sound you're hearing match all the criteria cited in this thread? More importantly, have you reviewed the video posted by Richard Straker in this thread and on YouTube?

ndmo

Sounds are very very similar, but I hear it slightly more metallic sounding on mine. but that might just be bad speakers. Low accel or constant speed causes the sounds. similar conditions.

Highplains

I would say that the acid test is hearing it at 1500 RPM. That seems to be the most common sign across the board. All driving modes, gears, etc. Myself and at least one other had, in addition, a low growl at 1000 RPM. If you're accelerating, you'll hear it as you pass through 1500 RPM. Using the paddles, you can use your cruise control to set it at 1500 RPM in the gear (and speed) of your choice. Doing that, it would sound off continually especially up a grade. The test that the engineer did on mine was the same to that done on Richard Straker's car and he found that the diff was making the noise all the time although more faintly at other than 1500 RPM.

ndmo

Alright, Ill try that out tomorrow. Thanks, is there a TSB floating around on this or is it just a known problem with no clear answer for now?

Highplains

No TSB or recall that I've heard off yet. Those who have read most of my latest posts are probably tired of me saying it, but I was told that if your dealer does not know about this situation, they should call the Technical Assistance Center to get instructions.. I'll be interested to see how your situation turns out. Although I had what is supposed to be a corrected diff installed last week, I'm still holding on to the idea of a buy-back just in case. The Z51 and the GS have a different diff than the base car so I'm assuming that I'd have to buy one of those two to get away from this mess if my "fixed" diff isn't the answer.

bjones7131

Don't think U will C a recall on this. By definition a recall has to do with a safety concern on a vehicle so this will prob. get a TSB at some point if this fix on Pete's car works out.

767guy

Has anyone reported that the "warble" is any more or less noticeable operating in V8 or V4 mode ???? Just curious.

Highplains

Seemed the same in both modes on mine.

Strake

It was the same on mine too. NO difference on any driving mode, gear, exhaust setting, or V4 or V8.

All about the 1500 rpm with light foot on the gas pedal, ESPECIALLY if going up any kind of incline.

Rebel Yell

It's like you live in my world Richard.

Strake

Yep, I know all about living in the WARBLE world....

I believe I was the first to post about this last Feb the day we picked up the car at Kerbeck and drove home. Started at mile 40....

My post didn't get any traction, little response. Bruce started this thread and I joined in, along with many others. I posted the YouTube video/ audio clip that was sent to the GM CEO and others.

My car was bought back by GM Engineering and used to tear down and get to the root cause and corrective action. The car went back to Detroit mid November.

Hopefully, I won't see any issues with the replacement Grand Sport !