I'm only at 22000km, mostly city. I thought at first it might be carbon due to all the short trips I take with it, but everything I can pull apart (MAF, TB, etc) all look fairly clean. I called GMC directly. They said they can't open a case without a dealer. The dealer says they can't do service without approval from GMC. They are pointing fingers at each other. I've opened a case with CAMVAP to try and get something done. I hear it can be quite a process. I was hoping someone here might have some smaller things I can check in the mean time.
Hello, I have a 2017 Sierra 1500, Double Cab, 6spd, V8 5.3. My truck idles rough. My truck also shifts hard, especially on downshift. Both of these symptoms are exacerbated significantly by having the air conditioner on. The rough idle is intermittent and feels like a miss. It shakes so bad sometimes my coffee will splash out of the cup into the cup-holder. It is not consistent. It a shudder every 0.5 to 3 seconds. At warm idle, the RPM sits just below 500rpm. At park, the RPM bumps up to 600-650. The shudder can barely be felt in Park or Neutral, but is still noticeable if you are paying attention. The hard shift is a clunk, mostly noticeable at lower gears (3-2 and 2-1) when downshifting. It becomes more pronounced on longer drives. Like I said, both symptoms get 200-300% worse when the air conditioner is running and when the engine is warm. The monkeys at the dealership say that this is normal and will not attempt diagnostics or a fix. There is no other dealership nearby. I've tried cleaning the throttle body and the MAF sensor; they are pristine. I've run injector cleaner through my tank, and used higher octane good quality fuel. Oil changes every 5000km. None of this has made a difference. I am running a range unit to turn of AFM, but this device doesn't appear to effect the issue either way. I noticed this barely and intermittently when I first bought the truck, but is is getting progressively worse to the point where its hard to ignore. What else can I do here, or do I just have to live with it?
I have this issue too. I'm pretty sure anyone with a 1500 who gets their truck dirty has this issue. Its a design issue with the OEM leaf springs. Fleet truck owners don't really care if the truck makes noise, so neither does GM since fleet trucks consist of most of their sales. The only people buying GM half-tonnes privately are the poor folks (like me) who haven't figured out that GM is not even remotely close to the same company they were 15 years ago. The noise is caused by dirt getting in between your leaf springs. Its like this in all the K2 series trucks. There is no permanent solution other than to replace the springs with aftermarket. Some folks are just power-washing the springs on a regular basis. Others are sticking rubber sheets or bicycle tire inner-tube chunks between the leafs. Some have had luck with aftermarket silicone lube spray. A lot of folks just live with it. The TSB that GM has is a low-cost band-aid to get you to go away until the warranty expires. The noise will always come back. In the 2019s, GM replaced the leaf springs with springs made from composite, finally catching up to what Ford and Ram started doing in the mid 2000's. For the K2 series, they have your money already so they don't care. If it bothers you, and you can't afford aftermarket springs, something like this is your best solution.
We don't know that. GM doesn't release their repair statistics. It is absolutely fallacious to declare that these trucks are running "without issues", when there is no way of knowing if that is or isn't true. All we know is that those millions of truck owners aren't running to the forums if/when they encounter problems. We do not know whether or not they actually are having problems.
Well, dirt creates friction, which makes noise. Its probably amplified by the ricochet down the axle and frame. This truck seems VERY sensitive to harmonics. I'm guessing the friction is momentary, like when the center of gravity of the truck shifts. This sounds like a "clunk", but its actually a very short "creak". I tried adding silicone lubricant (the aerosol kind) which is the only thing that has improved the noise it so far. I did it in stages to see what spot had the biggest impact. By far, the biggest improvement was when I sprayed the section where the axle seat sits on the axle under the u-bolt. I bolts seem tight, but I don't have any way of gauging the level of torque. Even if they were loose, they were just tightened 2 weeks ago. They shouldn't be loose already. I've not tried the rubber trick yet.
I tend to think it is quality control. GMs level of QC has taken a pretty big hit since around the time of the bailout. This is inevitably going to lead to more problems like this popping up, not just with one-off issues, but with the core design. Defects that everyone experiences. I remember reading companies like GM and Chrysler have a different engineering philosophy than most other car companies. Traditionally, when an engineer designs a vehicle, they submit a drawing to assembly, and that drawing is the final standard. If a parts manufacturer or assembly line does not conform with the drawing, then they are instructed to do-over, and match the drawing. Conversely, GM and Chrysler have a different philosophy; If a part manufacturer designs a part that isn't exactly to specification, GM and Chrysler won't necessarily send it back. If there are no immediately discernible problems with the non-spec part, they will amend the drawing to accommodate. This is just something I regurgitated from memory so take it with a grain of salt. I can't remember where I read it, but I've seen if a few times. If it was true, it sure would make a whole lot of sense, and explain why a lot of the issues we see with GM and Chrysler are shared by so many of their customers, and why the problems with other companies (Toyota's) seem to be mostly one-offs.
If they are off warranty, I would hope people are smart enough to not get it done at the dealer. Out-of-warranty work at dealers is usually drastically overpriced. Any mechanic worth his salt is not just going to replace a single bank if the lifters go. Get them all done. And when you get them all done, you might as well get the AFM deleted entirely. I've seen prices ranging from $2000 to $6000. I can't remember specifically where I saw it, but I seem to remember someone posting that they were recommended just to drop in a new engine It is not a small repair. I'm surprised there isn't a class action about this.
The oil didn't cause the issue, but it may have exacerbated it. The noise is caused by dirt between the leaf springs. Depending on what kind of oil was used, it can actually attract dirt, which will cause the noise. Only GM would design a leaf spring that you can't get dirty. Only GM would keep those leaf springs for over a decade before fixing it. The lubrication they use at the dealer is silicone based, and shouldn't attract dirt. The problem is that it washes away easy, so the noise comes back fairly quickly. I've heard that the issue is fixed in the 2019's. They moved the padding around or something. I don't know this for sure, but someone on one of the other threads has talked about it. I've also not heard of this happening on aftermarket leafs.
Yeah. I put this on a little over a month ago and it works like a charm 2017 Sierra 1500 5.3L V8 https://rangetechnology.com/afm-disabler/ Over 2000k later, and according to the economy computer, I've actually improved gas mileage. I do mostly city driving. Even if the lifters in this truck weren't garbage, I would recommend this device. It has drastically improved the way my truck operates, especially in low speed situations like parking lots and heavy traffic. The transmission seems to get confused less often and can actually decide what gear it wants to be in. I still get that clunk when downshifting between 3-2, but when my power-train warranty is up I'm going to do a full tune to hopefully fix that, disable AFM for good, and raise my idle over 550rpm to prevent the surging that is apparently common with the 5.3. If your lifters are already gone outside of warranty, then I would go as far as to do a full delete, which includes a new cam. If you take out of all that AFM garbage, the vortec/ecotec gasoline engines are actually second to none, and the engine will likely outlast the truck. If you are getting a range device, I would buy directly from range to ensure you get the latest firmware/model. I've heard stories about older stock being sold on Amazon which still have bugs that were resolved years ago.
Don't worry about it. The debate was stupid and pointless and derailed a legit thread. I think OP was the one who brought it back to life. Its still useful for other folks. The K2 trucks would have a pretty strong second-hand market by now, and this thread has some useful info.
You keep using that term "evidence". I don't think it means what you think it means. I think you are confusing "factual evidence" with "conjecture". Its an anonymous forum. Personal anecdotes from anonymous people are not "facts" and certainly don't qualify as evidence. I've never presented forum threads as evidence, or even pretended to. What i did say is that it was a "common concern". Right from my first post, that is all I have said this is. There are a number of threads of people being concerned about it. A quick search engine search will show that. You say I'm lying about these threads, but you've participated in many of them. Lots of people with differing opinions and results, but those threads do exist. Many of those people are saying they have positive results with cleaning (as I've linked). It doesn't make it evidence that a problem exists. Its just conjecture. But it is a concern that is stated commonly (hence: common concern). It could all be the same person with different accounts for all we know. I don't recall ever saying it was evidence. The only thing I would say would qualify as (weak) evidence that carbon is a problem is the fact that large manufacturers have spent not-insignificant amounts of money to fix this. We know this to be true because they have published it and its in the engine cut sheets. But that is an entirely different topic.
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