6 Speed Auto - Stutter, chuggle Issue

Janster · April 26, 2017

I know this has been beat to death on other forums... Some folks have this 'condition' while others don't. Those who don't have it - don't understand it and blame it on the driver. It's a pretty common issue with a lot of folks.

I have 2016 Canyon SLT - love the truck. 6 Speed Auto. Basically - the truck shifts too early - to save MPG's. It'll be in 6th gear around 45mph. However - when you slow down or coast a bit - get on the gas a little bit ... The truck stutters, chuggles, hiccups - whatever you want to call it. Kinda like it doesn't know how to downshift......unless you bury your foot in the gas to 'wake it up'.

I've had the truck to the dealership and they updated the Transmission programming. It got much better but not perfect. Fast forward to about 3 months - its worse than it was before the program update. From what I've read - the transmission 'learns' your habits (adaptive learning). ?? So...the update was only good for short period of time.

There are many theories about what you need to do to make this 'stutter' issue become un-noticable. Using Tow/Haul Mode all the time, Buying Premium gas, Manually shifting, get a heavier foot, learn how to drive it differently. Personally? I shouldn't have to do anything to a $40,000 piece of equipment.

Well..... I've been driving vehicles for 35 years and this is the first vehicle that's done this. I've tried different things myself, but I'm not all that happy about having to 'adapt' to something that GM doesn't seem to wanna fix. I've had the truck for a little over a year - I don't want something 'mechanical' to die because I didn't push the issue now (while warranty is here).

So, I guess my questions would be.... Anyone else have this? Were you able to get it remedied thru your dealer? What else could it be? Misfiring? Torque Converter? Fuel delivery? ???? Poor sensors?

The Programming ... Do they have the ability to TURN OFF the adaptive learning? It's almost like I need a master GM Tech to answer these questions and/or have suggestions on how to PUSH the dealer to dig deeper.

Anyway - Thanks ahead of time!

fondupot · April 27, 2017

Other people h ave been successfully eliminating (or greatly reducing) this issue by installing a Pedal Commander module on their 2015-2016 trucks wit 6 speed trans.

There is no way to turn off adaptive learning. Even if you could, the trans would likely still behave the same. Adaptive learning means that it adjusts constantly based on driving scenarios, i.e. towing, terrain, temperature, etc. It doesn't just learn once after a few hundred miles and then stop learning. It is a continual process always adjusting based off driving scenarios.

But I can feel your pain, because my 2014 Sierra with the 6 speed that I had before the Colorado was a clunk-o-matic. The only way I got that truck to shift acceptably is by getting a custom tune by Blackbear performance.

Knock on wood, my 2017 Colorado with 8 speed drives great. I am very happy with it.

Janster · April 27, 2017

Other people h ave been successfully eliminating (or greatly reducing) this issue by installing a Pedal Commander module on their 2015-2016 trucks wit 6 speed trans.

There is no way to turn off adaptive learning. Even if you could, the trans would likely still behave the same. Adaptive learning means that it adjusts constantly based on driving scenarios, i.e. towing, terrain, temperature, etc. It doesn't just learn once after a few hundred miles and then stop learning. It is a continual process always adjusting based off driving scenarios.

But I can feel your pain, because my 2014 Sierra with the 6 speed that I had before the Colorado was a clunk-o-matic. The only way I got that truck to shift acceptably is by getting a custom tune by Blackbear performance.

Knock on wood, my 2017 Colorado with 8 speed drives great. I am very happy with it.

I've had the Pedal Commander for about 2 weeks. It doesn't correct the stutter chuggle issue. If you set the PC pretty aggressively - it helps only because the truck senses a harder pedal push. That's about it. You don't have to press as hard to get it to downshift.....

And actually, I like the PC for being able to change the sensitivity of the pedal. Right now, I have it set to match my previous truck -I don't have to press down as hard to get it to do anything and I can feather it. But I guess, we'll see what the transmission 'learns' after using the PC over time.

I'm guessing GM has totally given up on the 6 speed. Their fix was to get rid of it completely.

I had done some research on tunes. I just don't want to put that much money into it. I just don't want to find out that something else is wrong with it (mechanically) that'll show up after warranty. There are a lot of guesses out there of what it 'could' be..... Assuming its the shift logic to safe MPG.

Psycholotron · December 17, 2019

I know this is an old thread and not sure if you ever found the solution to your problem.

I had the same exact issue you described and as hard as it is to believe , I replaced the canister purge valve and it resolved the issue. No more stutter or any type of delay when pressing the gas pedal down. I couldn't believe it fixed my issue either as that's not the reason I replaced it, but it did.

Hope this helps someone in the future.

cordellanderson · March 27, 2020

I had this happen on my 2016 GMC Canyon 2.8 Duramax.

Started having my engine stutter on the highway to and from work randomly and then one day it threw a code for the injector 4 and Stabillitrack messages saying it needed to be serviced and put me into limp mode.

The sound coming from the engine seemed like it was sneezing at first, then it seemed to mis-fire a couple times. When threw the service stabillitrack code I had to fully turn off my truck and reset the code with my obdII scanner, then was able remain normal running. I also found that switching to manual mode would prevent un-necessary downshifts and prevent the truck from going into limp mode. (this was how I drove it for the next month....)

I immediately added some Lucas fuel additive to add some lubrication to my fuel in hopes to clear that injector issue. (this seemed to allow me to at least drive my truck)

Solution: >>>>> I switched where I fueled my truck. I was getting my fuel and had been at Fred Meyer for the last 2+ years. I am thinking they changed suppliers or have some kind of contamination with their tanks. Either way I found a new source of straight diesel in my town and will be only going their from now on.