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Discussion Starter #1
Hello,

I have a 2019 3500HD L5P Dually.

I have been chasing down a shake in the truck since I bought it. Had tires balanced/Road force balanced by the dealers so that is taken out of the equation for me at this point. This definitely made the shakes in the truck quite a bit better but there is still a lingering issue that the dealer is saying "that's just what the truck does".

When I'm accelerating from 65-72, especially with a load, the whole truck will start to shake. When it's cold it's minor and just a nuisance. Once the truck warms up after 15-20 miles of highway it continues to get's worse until it get's to just a stable shake through the truck while maintaining in the 65-72 speed range. It seems to be tied to engine revs to a certain degree as I can feel it shaking at bit when accelerating at lower RPMS from 45 to 55 as well, but it's not as pronounced as 65-72. When towing it gets especially bad going up a hill/accelerating up a hill.

Once I let go of the fuel the shake completely disappears. This goes doubly so towing and going down a hill after a climb. If I accelerate faster than 65/72 and let off the throttle, there is no shake in this speed range, it smooths out completely as it decelerates. I don't need to put it in neutral/take it out of gear either.

I duplicated it for the tech and service manager and they acknowledged the truck is doing it and explained it as being "economy mode" to try and save fuel or some weird explanation so it causes some shaking, but it's a constant shake, so I'm not convinced. It went through 3 techs at the dealer apparently and they all think there is nothing wrong. They said they checked the mounts for cracking or any issues and didn't see anything that would cause this kind of engine feedback, they rechecked tire balancing and they did some checks to the transmission.

I'm kind of at a loss here as to what the issue is that could cause this vibration from the engine and give this info to get GM to actually fix it. I owned an LML before this that definitely didn't have this issue so I know it's not something the "truck just does".

Any insight is appreciated.
 

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I don’t know, but do you have a cts2 or something to monitor lockup of torque converter. It may be locking unlocking rapidly under acceleration.
 

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Discussion Starter #3
Is a CTS2 a tuner like the Banks? I don't have a tuner so I don't have access to this information. I was contemplating adding a banks Ram air intake+ banks derringer but since the truck shakes I hesitate to drop 1k to tune the truck if it's already having some form of drivetrain issue. Would a banks have Torque converter information as well?

I wanted to add, I also feel some feedback in the steering wheel with the shake that completely goes away when I remove the throttle. The best way I could describe the shake is that it feels like the truck is driving on a rocky/gravel surface while on smooth highway roads.
 

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No, it’s not a tuner, just a monitor. I have mine setup to monitor which gear and wether the converter is locked or not.
 

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I'm always suspicious when someone joins and immediately posts two 'difficult to resolve' issues on two different threads, but anyway....



Is this the same dealer feeding you the nonsense about the DEF usage?

Time to give up on the service adviser and move up the chain at the dealership.

Service manager, then GM, then the contacts listed in the back of the owners manual.

The def consumption and the vibration under load or NOT normal, no matter what the service adviser is saying.


Keep your cool.
As they say, "you'll catch more flies with honey than with vinegar."
 

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Discussion Starter #7
In terms of the def issue I was sharing my similar problem to the op. That wasn't something inoriginally posted about. They reprogrammed it as I said and my DEF consumption seems to have leveled out. I have 2500 miles since the reprogram and I haven't gotten a warning light for def low since. I was just saying I've encountered the same issue. I am also not going to that dealer anymore since it took them 3 days to road force balance 2 tires. I'll post that in the other thread.

The service advisor rode with the director today, the director was the one that made up the story about the economy mode and told the adviser to tell me. The adviser seems to believe me and told me to bring it one day when its warmed up and the issue is really rearing its head. The problem is I'd need my trailer hooked up to make it so obvious they can't just disregard it. Its hard for me to do this as its also the trailer im living in as I fulltime rv right now so I cant just hook it up and bring it to them with the trailer attached.
 

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How many miles on the truck and when was the last time you changed the fuel filter? I had this happen not on my truck, but a different diesel and it did the same thing. Ended up being a plugged up fuel filter that didn't register as being plugged.
 

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Discussion Starter #9
Truck has 4k miles. Bought it in October 2018. It's done this since I bought it brand new. It seemed ok on my test drive, took it up to highway speeds but I didn't feel much, on my drive home from the dealer which was a much longer drive I felt it. That's what started the saga.

How difficult is it to remove the filter on this, does this require the tank to be dropped at all?
 

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i own a 2019 chevy dually with the exact same problem. same rpm range. new tires and all that stuff. wondering if its something to do with the torq converter.
 

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My brother went through the same type thing, ended up being a bent rim. no accidents and says he did hit some bad potholes that you wouldn't think would bend a rim. the people who put on many different tires where dumbfounded, but finally one of them looked at tire/rim as it spun on balancer and seen the rim. got a different rim and it went away! he has aluminum rims on the rig.
 

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Truck has 4k miles. Bought it in October 2018. It's done this since I bought it brand new. It seemed ok on my test drive, took it up to highway speeds but I didn't feel much, on my drive home from the dealer which was a much longer drive I felt it. That's what started the saga.

How difficult is it to remove the filter on this, does this require the tank to be dropped at all?
Fuel filter is external (not in the tank) and very easy to change. Below is a video link on how to change the filter. Make sure you wear eye protection and dress appropriately regarding the potential for diesel fuel splashes while changing the filter.

 

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Hello,

I have a 2019 3500HD L5P Dually.

I have been chasing down a shake in the truck since I bought it. Had tires balanced/Road force balanced by the dealers so that is taken out of the equation for me at this point. This definitely made the shakes in the truck quite a bit better but there is still a lingering issue that the dealer is saying "that's just what the truck does".

When I'm accelerating from 65-72, especially with a load, the whole truck will start to shake. When it's cold it's minor and just a nuisance. Once the truck warms up after 15-20 miles of highway it continues to get's worse until it get's to just a stable shake through the truck while maintaining in the 65-72 speed range. It seems to be tied to engine revs to a certain degree as I can feel it shaking at bit when accelerating at lower RPMS from 45 to 55 as well, but it's not as pronounced as 65-72. When towing it gets especially bad going up a hill/accelerating up a hill.

Once I let go of the fuel the shake completely disappears. This goes doubly so towing and going down a hill after a climb. If I accelerate faster than 65/72 and let off the throttle, there is no shake in this speed range, it smooths out completely as it decelerates. I don't need to put it in neutral/take it out of gear either.

I duplicated it for the tech and service manager and they acknowledged the truck is doing it and explained it as being "economy mode" to try and save fuel or some weird explanation so it causes some shaking, but it's a constant shake, so I'm not convinced. It went through 3 techs at the dealer apparently and they all think there is nothing wrong. They said they checked the mounts for cracking or any issues and didn't see anything that would cause this kind of engine feedback, they rechecked tire balancing and they did some checks to the transmission.

I'm kind of at a loss here as to what the issue is that could cause this vibration from the engine and give this info to get GM to actually fix it. I owned an LML before this that definitely didn't have this issue so I know it's not something the "truck just does".

Any insight is appreciated.
Tire balance may or may not be your specific issue ... but for this issue I put on a set of dynamic wheel balancers ... because random tire tech’s would consistently misplace a weight during the rotate and balance of my tires.

Can’t say enough good things about these balancers. My truck is glass smooth on the highway now ... even when the tire tech misses the mark regarding tire balancing.

Here is a link if interested:

https://www.centramatic.com/wheel-balancer.rhtml?modelNumber=300-320
 
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