Shudder/Vibration Issue

teamkeystone · April 15, 2019

On 1/18/2019 at 4:38 PM, bigman32hockey said:

Thanks teamkeystone. Glad to here I'm not the only one who has experienced the lurch after remote starting. I totally agree with you about the shifting. Mine seems to shift much harder from 1st to 2nd. After that, it does seem to smooth out somewhat. I just don't think this is one of the better transmissions available. Sad to say with it being such an expensive vehicle.

So now that the weather is warming up, I have been experiencing the "lurch after remote start" again. Which makes me think that it has something to do with the AC. Maybe the AC is running during remote start and then kicks off when I turn the key.

thekevin · April 16, 2019

I have 16k miles on my 2018 5.3/6spd LTZ I bought in November. I haven’t had any studders out of mine but it does seem to go full on retard sometimes when trying to decide the right gear. I wonder if changing the fluid to the newest GM recommendation would be a good preemptive move. I am about to start pulling my 27ft camper with it for the summer.

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Rick Murphy · May 18, 2019

I just got back from the dealer with my 2018 siverado 5.3 6 speed transmission with a vibration problem between 45 and 55 mph and they are ordering a new torque converter for it and will install it next week I will keep you guys updated

bigman32hockey · May 20, 2019

I currently have about 6,500 miles on my '18 6.2L. The transmission flush was done on mine at 1,564 miles. Since then I have not experienced any shuddering. However, my truck still shifted like crap and clunked all over the place. When I traded in my previous Silverado for this one, I was running a Range AFM Disabler. I put in in the new truck from day one, but I felt like it made the truck shift terribly. After about 5 days of using it I took it out. Then came all the shuddering issues. After that was taken care of, I never put the Range unit back in for fear it would make it shift bad again. But after about 4,500 miles I couldn't take it any more. My truck clunked and banged on downshift ALL THE TIME! I opened up a case with GM Customer Care and complained to them about the issues I was having. The dealership said there was nothing they could do to fix it, and I pretty much believed them. It's inherent in the transmission. After getting nowhere with the dealership or GM Customer Care I said screw it and tried the Range unit again. Holy crap...what a difference! I mean a night and day difference. 95% of the clunking is gone. The lurch I would feel just as the truck was coming to a stop is gone. It drives so much more smooth. It really is a drastic improvement. GM is killing the driveability of these trucks with the stupid AFM. In constant V8 mode I barely lose 1mpg. Who the hell cares about 1mpg if the truck drives like it should? If you are like me and are completely fed up with your truck, try one of these Range units or have AFM tuned out of your truck. You will not be disappointed. I actually love driving my truck now, and I was almost ready to lose my shirt on a trade in for a 2019 Ram.

Lamekurt · May 20, 2019

13 minutes ago, bigman32hockey said:

I currently have about 6,500 miles on my '18 6.2L. The transmission flush was done on mine at 1,564 miles. Since then I have not experienced any shuddering. However, my truck still shifted like crap and clunked all over the place. When I traded in my previous Silverado for this one, I was running a Range AFM Disabler. I put in in the new truck from day one, but I felt like it made the truck shift terribly. After about 5 days of using it I took it out. Then came all the shuddering issues. After that was taken care of, I never put the Range unit back in for fear it would make it shift bad again. But after about 4,500 miles I couldn't take it any more. My truck clunked and banged on downshift ALL THE TIME! I opened up a case with GM Customer Care and complained to them about the issues I was having. The dealership said there was nothing they could do to fix it, and I pretty much believed them. It's inherent in the transmission. After getting nowhere with the dealership or GM Customer Care I said screw it and tried the Range unit again. Holy crap...what a difference! I mean a night and day difference. 95% of the clunking is gone. The lurch I would feel just as the truck was coming to a stop is gone. It drives so much more smooth. It really is a drastic improvement. GM is killing the driveability of these trucks with the stupid AFM. In constant V8 mode I barely lose 1mpg. Who the hell cares about 1mpg if the truck drives like it should? If you are like me and are completely fed up with your truck, try one of these Range units or have AFM tuned out of your truck. You will not be disappointed. I actually love driving my truck now, and I was almost ready to lose my shirt on a trade in for a 2019 Ram.

I wish I could say the same. I ended up getting a diablosport tuner with a custom tune in hopes to fix my issues and it certainly made my truck bearable but it still clunks when slowing down up hill. I have 0 shudder issues now though! Still sucks that I spent all this money and then some more and the truck still clunks and downshifts rough from time to time. I want to trade really bad but financially it’ll put me in the hole so I guess I’ll have to deal with the “bearable” drive..

bigman32hockey · May 20, 2019

I hear where you are coming from. My truck is not perfect, hence why I said 95% of the issues are gone. It will get confused once in a while like if I let off the gas at the exact wrong time. I do notice more issues when the transmission temperature is cooler (below 90). As it warms up it definitely smooths out. I still have harder shifts from 1st to 2nd, but I can alleviate some of that by accelerating more slowly. Not that I should have to do that, but it does work. The transmissions in these trucks suck. I shouldn't have to buy aftermarket parts to make it driveable, but I do. Disabling AFM has made it head and shoulders better for my truck. Would I buy another GM product with the 8-speed transmission? Not in 100 years. But at least I have a truck that drives ok most of the time and don't have to lose $12k to trade it in with 6,500 miles on it.

Lamekurt · May 20, 2019

4 minutes ago, bigman32hockey said:

I hear where you are coming from. My truck is not perfect, hence why I said 95% of the issues are gone. It will get confused once in a while like if I let off the gas at the exact wrong time. I do notice more issues when the transmission temperature is cooler (below 90). As it warms up it definitely smooths out. I still have harder shifts from 1st to 2nd, but I can alleviate some of that by accelerating more slowly. Not that I should have to do that, but it does work. The transmissions in these trucks suck. I shouldn't have to buy aftermarket parts to make it driveable, but I do. Disabling AFM has made it head and shoulders better for my truck. Would I buy another GM product with the 8-speed transmission? Not in 100 years. But at least I have a truck that drives ok most of the time and don't have to lose $12k to trade it in with 6,500 miles on it.

Exactly my thought man. My first GM truck and because of this, possibly my last, but I am happy I have saved my investment with my tune!

bigman32hockey · May 20, 2019

Out of curiosity, were you able to tune transmission parameters on your truck? I was under the impression you couldn't because it was locked by GM?

Lamekurt · May 20, 2019

46 minutes ago, bigman32hockey said:

Out of curiosity, were you able to tune transmission parameters on your truck? I was under the impression you couldn't because it was locked by GM?

You can change shift points, firmness, and torque management with the intune i3 platinum. There’s also parameters for the ECM(engine) as well. The platinum is used for the newer GM trucks and I believe when you purchase it, it comes with an unlock! Mine did because I got it through a guy who does custom tunes and he worked it all into a package deal.

huntr1117 · May 20, 2019

An aftermarket tune is pretty much the only way to make the 8 speed act like it should. I was actually pretty happy with the last flush I had and the new fluid. It wasn't perfect but it was pretty damn good. Then I tuned it and it's so much better. 2016 and under you can tune the 8 speed trans. 2017 and up the tcm is locked. You can have the tcm unlocked by sending it into hp tuners and paying the fee. Then have the motor and trans tuned with hp tuners.

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Ozer · May 24, 2019

2014 sierra 6spd with 120k miles

Just got a call from dealer saying its the TC. Its been shuddering and kicking while under light load. Waiting for a call on how bad the damage is, ughh..

Edited May 24, 2019 by Ozer

Lamekurt · May 24, 2019

6 minutes ago, Ozer said:

2014 sierra 6spd with 120k miles

Just got a call from dealer saying its the TC. Its been shuddering and kicking while under light load. Waiting for a call on how bad the damage is, ughh..

Let me know how much because the dealer is telling me they can’t duplicate the problem so I’m honestly at the point of paying cash to have someone (maybe not even the dealer), change my TC.

Gagliano7 · June 7, 2019

I put the AFM disabler on my truck with 16 miles on my truck. Trans shifts perfect and never hunts for a gear. 18 sierra 6.2 8 speed trans. The only time i ever felt something funny was the day i hit the disabler with my knee and accidently unplugged it. I think AFM is 90% of the problems with the trans. Once i am out of warranty and if i decide to keep this truck i will have it tuned and replace all the AFM lifters.

ForumUser · July 28, 2019

AFM, IMO, is not the problem with the transmission - we know it is the fluid.

Now, disconnecting the AFM and losing warranty coverage if it is trackable change - may make it smoother ... but ya lose several MPG in doing this, right?

My 2017 (I've posted several times in this thread) is no longer shuddering. Just completed several thousand mile round trip from north Florida to Aspen, Colorado. No shuddering, great MPG (28-29 easing down long 65 mph grade on two lanes in southern Colorado) .. average close to 24 MPG for the entire trip. Smooth, comfortable calm driving at 80-85 with AFM engagement not even perceptible unless you are trying to hear it and watching the instruments.

Still has that weird 2-1, 2-1 clunk under partial throttle, though.

Rick Murphy · August 4, 2019

On 5/18/2019 at 3:55 PM, Rick Murphy said:

I just got back from the dealer with my 2018 siverado 5.3 6 speed transmission with a vibration problem between 45 and 55 mph and they are ordering a new torque converter for it and will install it next week I will keep you guys updated

They put a new torque converter in my truck with no change to my vibration so I took it back. The dealer said it could be the motor mounts so they were ordered and installed new ones and I was told that the truck would be ready Friday The dealer called me Friday and said there was still a problem and they have new trans fluid ordered and should come in in a few days I am not to optimistic at this point but I will keep trying to get this issue fixed