gybob

I had a 2014 Silverado before I had this shaking 14 Sierra. New off the lot, the Silverado shook bad. They told me it had been sitting on the lot too long and tires were probably flat spotted. After a couple hundred miles, I brought it back. One of the rear wheels had TWENTY OUNCES OF WEIGHTS ON IT!. ON A BRAND NEW TRUCK! Way to go Chevrolet! I'm not kidding. They showed me. They replaced two tires. The truck rode perfectly after that. I wanted the Sierra to have additional bells and whistles. I've owned NEW 99, 02, 03, 05, 07 and 14 Silverado's. Also had a new 11 F150. No problems with any of them. This is my first GMC. I thought surely "professional grade" will ride nicer than the Silverado. I feel kind of like the village idiot. Learned a lesson here the hard way. Wish I still had the 14 Silverado.

For what it's worth, my first service visit resulted in "wheel balance fixed it." It didn't. Strike one. The second visit lasted 16 days. The rear axle assy was replaced. Driving at "around town" speeds to break in the new rear, the truck felt good up to 50 - 55 MPH. It used to shake bad at that speed. At around 275 miles, it gradually started shaking again. At about 380 miles (on the new rear), I took it on the highway. Not good at all. 70 - 75 shakes bad. She seems to be smooth when stone cold. It gets worse as things warm up. If I didn't know better, I would swear that it's a tire problem (stock Goodyear Eagle LS2, 20") but the smart guys swear that all my tires are balanced properly and measure around 16 lbs of road force variation. Dammit. Strike two. Notified dealer that I would like a third and final repair attempt (per GA lemon law). Was told on 29 Dec that they don't know what else to do and that they want an engineer to look at it. As of today, they're still waiting for the GM engineer for this area to be available. The fact that the new rear started out smooth and got worse as it wore in doesn't make me feel too good about this. Or.... Maybe the new rear is good and a tire or the drive shaft/u-joint developed a problem. Multiple defects and/or installing a defective new part really challenges the troubleshooting thought process. Enough rambling for now. I really like (actually love) this truck aside from the shaking. It's equipped exactly as I like it and the price was right. If only it rode like a new truck... I hope they can fix it.

Well folks, my ordeal came to an end today. My 14 Sierra 1500 SLT with 1750 miles on it does not shake any more while going down the road. My story: By the time the truck had about 1000 miles on it, I realized that that the driveline vibration was (1)unacceptable and (2) not going to go away by itself. Took it to the dealer. The tech said that two of the wheels were out of balance. One by 3/4 oz and one by 1.5 oz's. Knowing this to be BS, I went ahead and took the truck. Of course nothing about the ride was different. Brought it back a couple of days later and told the service writer that "this is repair attempt number two - please troubleshoot and repair my problem." Service writer explained that at this point GM has a LOT of driveline vibration issues with this series of trucks and they do not yet have a solution. He put me in a loaner, a 2015 Yukon XL. I told him "take your time". A week later, he told me to come and get the truck. When I got there, he told me that they had been able to improve the road force variation on the two rear tires by two pounds. BS again. It doesn't take a week to match mount two tires. Not good. I arrived, ready for a spirited discussion and seeing a buyback in my future. At that time, service writer told me that GM tech had just called and asked them to use the electronic vibration analyzer to troubleshoot the problem. I jumped in that sweet loaner and left. Two days later, service writer asked me to return the loaner and drive my truck while waiting for a rear axle assembly to come in. Too much or too little pinion to ring gear backlash will cause problems, but not vibration. I was told that there is a VARIATION in backlash during a ring gear revolution. Wow! That makes sense. The backlash should be equal (or very nearly so) between the pinion and ALL of the ring gear teeth. Two days ago, I dropped it off to have the rear axle assy replaced. It came in COMPLETE, including rotors and calipers - ready to bolt up. Got my truck back this morning. It now rides like a new truck! During the last visit, all 4 wheels were scratched due to improper tooling being used on the wheel balance machine. I now have four NEW wheels. No pushback whatsoever about the wheels. Some lesson learned: The dealers (ALL of them - all brands) do not have the competent techs that they wish they had. Based on an experience that I had with a 14 Silverado (same size wheel/tires), I was certain that the tires were the issue. Had the dealer done as I insisted in the beginning, the tires would not have helped and they would have been out a lot of money. As frustrating as the first two visits were, I believe that my remaining calm and respectful contributed to these folks continuing in earnest to try to resolve the problem. I'm not happy that they (twice) tried to give me a "let's hope he'll go away and not come back" non solution. I respectfully let this be known. See 1. above. I feel like we now have a good relationship. I'm grateful to these folks for properly repairing my truck. I really like my truck now.