Rick35

Its been several years and a lot of aggravation since my last post. I wanted to add a conclusion that I finally fixed the problem. As someone suggested way back in the posts I added a disabler and the problem is gone. My gas mileage is a little less but I don't feel the shudder as the engine stays in V6 all the time. I should have done this a long time ago!

I first noticed the shudder around 11,000 miles so I don't if it is related to a break in period. I got an oil change at a different dealer last week and I asked the service guy if he knew anything different about the issue. He confirmed that GM considers this to be normal. He knows all too well as he has the same model and the same problem I do.

The service manager said GM considers the condition to be normal. That is a bunch of crap. I'm going to try another dealer but I'm not hopeful.

I have had discussions with my service people a couple of times about possible engine problems and they really believe the issue is in the exhaust. I was in getting an oil change on Friday and told them I wanted to start replacing parts. I want to start with the exhaust and maybe end up with the engine. They can't fix the problem but they want me to believe its not the engine or that the shudder isn't causing engine wear. I'm not buying it. Priority is vacation and I'll reconnect with them when I return.

And I should add that the service writer I deal with says that I'm the only one of his customers with this issue.

Its been a few months since my last post and I wanted to let people know that my shudder problem is worse. Its especially noticeable around 35mph but I also get it at highway speeds. I'm heading back to the shop to see if there any new ideas about fixing the shudder. Since GM didn't offer enough money to help a trade I'm going to recommend that they start replacing parts starting with the exhaust system. The service manager mentioned it early on and I didn't take him up on the idea.

GM offered $5000 trade-in assistance to be used on a new purchase. I had to make a deal with sales including the tradein of my 2014 Silverado. They didnt offer me enough to make it worthwhile. If I did buy a new truck I would have had to take out a new loan which would mean an extension of 18 months which equates to about $9000. And that included the trade in assistance. On top of that I didnt want an 8 cylider and looked at a Colorado. I traded in a Colorado and forgot how small it was. And there were no deals. So I decided I liked my truck more than the other options and decided to keep it.

I talked to GM today. First I received an email saying that my email was received and I would hear from a senior advisor within 24 hours and then I received a call late this afternoon. Most of the discussion was about me explaining what the problem was and ended with the advisor asking me what I wanted to do. I added that I was not the only one to experience the problem based on exchanges with other owners (on this forum) and this should not be a surprise for GM. The advisor was going to have a discussion with the dealership and we're going to talk again later this week.

Its been a few weeks since my last posting and I figured I needed to provide an update. My vibration/shudder issue still exists although it is slightly better. I scheduled another appointment with my dealer thinking they could add another dampener. Service called and told me the one dampener is the only fix for the problem so I cancelled the appointment and asked for guidance in how to initiate a buy-back. The guidance received was an 800 number. I found a GM warrranty/lemon web page and sent an email to GM and am waiting for a reply. There are a number of concerns or unknowns about this condition with few facts: 1. V4 to V6 shudder appears to be unique to 4.6L engine. I could not find any posts where the issue occurs on V8's. 2. Bulletin from Oct 2014 talks to AFM vibration issue and addresses exhaust mounts and bolts 3. Exhaust vibration has been happening for years on many vehicles and various dampeners have been used to counteract vibration and to reduce noise. 4. Dampener used in my situation was employed two years after model year was introduced. It was described as a new fix for the problem. Why now? It took two years to come up with a resolution (that doesn't work)? 5. My issue surfaced at 10-11,000 miles - no issue prior to then. Why now? 6. There is no information on what is causing the issue although GM is holding to its vibration dampening solution. My issue is that I don't know what is going on in the engine. My plan was to run the truck for ten years and now I don't know if that will be possible. I don't know what I'm experiencing is causing any damage to the engine and I believe I need to get out of the vehicle now while it is in otherwise great condition. Hopefully GM will help me do it.

I've had a chance to do some straight highway driving this weekend and unfortunately some of the shudder still exists. I think I notice it now because the road is smooth and also because I'm looking for it. If I didn't know it was a problem I don't know if it would bother me. I need to talk to service on Monday as a follow up and will see what they think. I may have to live with it. But it is much better. Maybe I'll hook a small bungie onto the clamp and see if that helps. It may help put a little tension on the pipe to take up what vibration remains.

Thanks to everyone who shared their experiences. Hopefully this can now help you get your trucks running smoothly.

It worked! Now that you see this thing you could do it yourself with a few scraped knuckles. If you could get the part, that is.

I tried again and found a brown cylindrical object attached to the exhaust in front of the catalytic converter. After not finding anything earlier I went back into the house and googled dampener again and I found a photo of an exhaust dampener from a few years ago. Mine looks just like it. From what I found from the old post it sounds like there's weight in the cylinder that dampens the vibration of the exhaust. The service order I received from the field engineer correctly called it a dampener and not a damper which is something different altogether. I'm new to the forum and certainly new to uploading photos and hopefully the photo loads correctly. [

I crawled under the truck tonight and can't find anything new. The adaptive valve is looking original and that's what I thought was the culprit. There was a rubber mount that looked kind of new but I don't know if thats what they call a damper. All I know is that I'm not feeling the shudder.

I picked up my truck tonight and there was no indication of shuddering on the way home. I need to drive it a bit more but I think they fixed it! There was no part number for the damper on the repair order but I would think GM will make it available to dealers now that they have a fix. I felt kind of like a guinea pig in all this and I'm still surprised they hadn't figured it out until now. Hopefully they can get the fix out to others and we can get back to enjoying our trucks.

If I can self diagnose I think the issue is the exhaust adaptive valve. I just googled it and there are a lot of postings at various forums. Its purpose is to stop noise and vibration and in particular "V4 drone" and if its the culprit its doing just the opposite. I hope to get a definitive answer when the truck is in for the fix. Its starting to make sense. I hope.

That's too bad about your dealer. Mine has been great. My truck is going in for the procedure on Thursday. I've got a loaner lined up and will drop it off Wednesday night. It will be out of recovery and ready to go home Thursday night and hopefully cured.

I would think GM would extend the warranty for that if you have been trying to get it fixed. What's interesting is that I didn't have any problems until around 11k miles. I'll get more info on the fix when I go back in. They thought it would be in a week or two.

When I heard the word "dampener" used I googled it and found there is a "damper" at the exhaust in the pipe to reduce vibration/sound generated in V4 mode. I still find it strange that this is a problem still after two years with 2014's on the road. And, there have been AFM vibration/sound issues in prior years. I found posts from 2007 that sounded similar to this problem and not just with Silverados or Sierras. I was getting nervous that there wasn't going to be a solution after yesterday's trip to the shop. I' m encouraged by the efforts and I'm satisfied with the attention from the dealership and GM. The word from the field service engineer was that he was confident of the fix. I was especially happy to hear that it was definitely not in the engine which worried me about future wear and problems after the warranty is up. After the problems GM brought on themselves previously it does look like they're doing the right things to make it right.

The GM field engineer checked out my truck today and confirmed that the problem is a vibration in the exhaust. There's a GM tech bulletin from October 2014 that describes adjustments to the exhaust but it didn't work for me in a previous repair attempt. The latest fix is a custom part that GM needs to make. That sounds strange considering there have been 2014's on the road for almost two years. The service guy confirmed that there is something going on with some 4.3's and it is related to switching from V4 to V6. I guess it makes sense that there could be some vibration as the cylinders start up. Maybe its a change in the engine balance during the transition. It is hard to believe that a vibration can be that pronounced. So I'm on hold again waiting for the part.

GM field service is coming to check out my truck this week. I can't imagine he's going to do something the local techs didn't already do but I hope I'm wrong. Generally there seems to be a focus on a vibration at a particular frequency but it sure feels like more than a vibration. Dealer service already checked and it wasn't what my problem is. They said it had to do with transitioning in and out of v4 prematurely. Sounds like a computer or sensor problem to me but they're the experts.

What was the trade-in assistance if you don't mind me asking.

I'm getting a shudder in my 2014 Silverado when the engine goes from V4 to V6. I've been to the dealer twice and now we're waiting for Field Service to contact the dealer about when they'll be in the area to check my truck. Its been a couple of weeks and still nothing from GM. The dealer tried a couple of things and if anything only made it worse. I'm getting very upset about the lack of communication with GM to the dealer. I haven't contacted GM directly yet as I'm not sure that will do. The dealer service has been good and I think they're doing the best they can. Any ideas?