Trbrown47

So, I have followed this thing since last July, and I am done with it... Here is where I am; GM has offered zero assistance and have denied the problem, doing nothing. The hell with the bums. BBB sided with GM ( follow the funding and it is easy to see why). Also gave the BBB a failing grade when the state asked for feedback. Filed a formal complaint with the State Attorney Generals office against GM Fired the dealer, the hell with them too (and offered my kids money NOT to buy anything for this dealer, or GM for that matter). Lowes did help reduce the vibration for me though; they sold me four 60lb sand bags that I installed in the box, forward of the axle Plan to sell or trade for non-GM ASAP SIGNING OFF...

You are in for a long and very uncomfortable ride.1. No, because GM says there is no vibration issue 2. Apparently so, nearly a million hits on this site alone tells the story 3. No, because GM says there is no vibration issue Some dealers are trying to help, mine has dumped me. BBB arbitrator sided with GM (follow their funding and you'll see why) State Attorney General's office will do nothing Until this thing hits GM squarely in the wallet, they will do nothing Bottom line: you're stuck...

Join the party, it seems most of the dealers are drinking the GM Cool-Aid, with "it's normal". Mine dumped it back on GM and simple stated on the RO, "no fix available". I have scanned many of the over 800,000 hits on this web site; there are a lot of pissed off owners who will think twice about buying another GM product. I've driven GM trucks for the past 20 or so years and have never had vibration issues like I now have with my 2015 Sierra Denali.

I have noted a couple of things that might be related to my vibration. One was tire pressure; less vibration when pressures are below 30lbs, like on a cold day. I believe it to be a dampening effect. Second, M5 vs M6; less vibration in M5. But I wonder if this is because it also keeps the engine in V8 (vs. V4). I am wondering about a couple more theories(which is all I have because GM doesn't give a damn). One is related to outside temperature. Could the differential fluid viscosity be higher on a cold day, thus reducing vibration? The other is related to cab load. I believe the vibration could not be reproduced during my BBB arbitration because there were 5 adults in the truck (or an additional 500lbs over what is normally in the cab). The GM engineer noted it would dampen vibration. You know, I've told 20-30 folks about my issue and talked to a few that have it as well. At some point this has got to start hitting GM in the wallet (unless they are just stupid).

I believe GM is very well aware of this problem, they just will not acknowledge it. (Within the 800,000 plus hits on this site, there are indeed hits from GM Customer Service.). The canned response appears to be, "it's normal", even though thier marketing and advertising say the Denali rides like a luxury car. In my case, the BBB arbitrator acknowledged the vibration when the GM Engineer would not. I would suggest that until vibration is defined in technical terms, with a specification limit, and it can be shown that limit is exceeded, there will be no case and no fix.

Just completed the BBB Autoline process. In my case, a losing effort. Even though I had my ducks lined up; contact detail, copies of RO's, even videos, when 5 adults piled into the truck for a test drive that suppressed most of the vibration the arbitrator said I didn't reach the "substantial" level for the state of Ohio Lemon Law. He admitted he felt the vibration just as most everyone in the forum has described, but he thought I was too sensitive.I referenced this forum with nearly 800K hits and this really put the GM reps on the defensive. GM was also silenced when I referenced their advertisements quoting how the truck rides like a luxury car. There appears to be a problem with these trucks, but GM refuses to admit it, as many others here have noted. It would be interesting to see real stats on the numbers of formal complaints the BBB is handling with this issue.

Possible solution to vibration: 1. File a complaint with the BBB 2. Go to arbitration 3. During the test drive, ensure 5 adults (2 from the BBB, 2 from GM, and you as the driver) are along for the ride. You see this adds close to 600 lbs which dampens vibration and does not allow you to reproduce the vibration for the BBB Arbitrator. The GM Field Service Engineer agreed the additional weight will indeed dampen vibration, and we proved it! (Unfortunately, I neglected to bring this up with Arbitrator during the test drive.) So, a sand bag test is underway (Lowes 60 lb tube sand bags). Will report findings, but I'm not sure what my next step will be if my test is conclusive. I'm not crazy about running around with several hundred pounds of sand bags in the box though...

My disappointment lays with the dealer thus far. I took my 2015 Sierra Denali in for vibration. The tech took it for a ride and returned to tell me there was design defect causing the vibration; fuel management v4. He didn't put it on the rack; he did no inspection, no balance check, no RFV check, no nada. I took it back a few weeks later with data I collected on when the vibration occurred; v4/v8, speed, tire pressure, 4wd/2wd/auto, and road conditions. No significant cause jumped out. I gave the dealer service advisor the tech the data. The same tech drove it again. He also drove another similar vehicle. (He claimed it had the same condition.). He checked RFV and declared the numbers in spec (17, 15, 12, and 4lbs) and made no vector adjustments, nor balance adjustments. The RO simply stated no fix available for vibration caused by the fuel management system. Basically, the ignored the data (some 80 occurrences over the period). Based on past experience with RFV, if properly done (with wheel to tire vectoring), it will probably solve most of my issue. So, the battle rages on...