[ChewySchu]

I have a 2017 Canyon Midnight Edition and I started noticing an issue with the way it sometimes shifts. What will sometimes happen, and usually only when I've just started out from a stop or am rolling in first gear, is that the engine seems to downshift unexpectedly, I get a little bit of an engine race, and then I get a pretty hard shift back into gear. Not only do I feel that shift, I hear a pretty good "clunk" as well. I know - how do you "downshift" from first gear? I can't explain it, and unfortunately I can't recreate it for the service techs. If I didn't know better, I'd say it shifted into neutral and then back into gear, but I don't get THAT much of an engine race. However, the jerk and the noise sound like maybe a shift from neutral into gear while the truck is rolling. And it's not just me, it's happened to my wife, too. She refers to it as a "lurch", which is as good a description as any.

All the local service guys tell me is that nothing like this has been reported, and their computers tell them that everything checks out OK. Naturally, I can't recreate it on a test drive with them so they have nothing to go on.

Otherwise, I love the truck. I'm just trying to find out if anyone else has had the same experience, or better, had it and been able to resolve it.

 

[Hunter62]

Usually that happens when tranny thinks it is going to shift into second and you give it just enough gas that it downshifts. It gives a big clunk and jerk. It will also do it when say, slowing down at a stop light, almost to a stop and light turns green, you give it gas while it is in second and it downshifts to first, big clunk....
even the full size Surbubanes, Escaldes Silverados do it.... evry now and then I catch mine in between like that, really nothing can be done that I know of

 

[coolformula]

Think they all do it. The old cars with 4 speeds knew it should be in first at that speed. new cars have so many gears it gets confused if it needs 1st or 2nd. I think its the nature of the beast.......

Progress.........

 

[ChewySchu]

Thanks. I thought that might be the case, but was really hoping it was something that could be corrected since it seems to happen often.

 

[hyperv6]

Yes it is common. I note it is often when you are in first step light on the gas and lift off before the shift happens it up shifts to second gear hard. Mote my observation is it is an up shift issue not down shift as you can down shift from first. If you go to the dealer this may help not calling it a down shift.

I note as long as the drive line has a load it is smooth as glass but unloaded this hard shift from first to second can happen.

Mine was worse before I had the transmission replaced with a seal leak issue that was not related but once in a while I may get a harder shift than expected.

I also note with a load in the truck I have never had it happen either. It is almost like there is some added play in the drive line in first gear.

 

[KMPrengerMO]

Its all in the way they have these tuned. GM knows there is a problem and a fix is (hopefully) on the way in Q1 2019. The shift and torque converter issues are found pretty much everywhere the A8 transmission is used (various Chevy, GMC, and Cadillac vehicles).

I have a 2016 Camaro SS with the 8 speed transmission. I came across this on the Camaro forum I belong to. It also lists the Colorado and Canyon. It specifies the upcoming fix is for 2019 Colorados and Canyons, and says if the 2017 or 2018 trucks experience shudder, to replace their TC, but it also says that is part of the 2019 fix that is coming...so pay attention guys. I think this will be one to look out for!

If you can't read the image below well, try viewing the link directly here: https://www.camaro6.com/forums/attachment.php?attachmentid=960024&stc=1&d=1539088342

 

[Xwd]

This probably isn't related to the torque converter issues mentioned above.

I think I've experienced the OP's description in about every automatic trans ever made for a light duty vehicle. If you're rolling along in 1st gear at idle and you creep up to the first shift point, say, 8-10mph, and you give it gas, the RPM's will raise as it builds pressure in the torque converter again to the point where the engine speed matches the road speed in that gear because the TC isn't locked. If you're at the minimum point to shift to 2nd, that's what the transmission will do. And because you don't really have any real momentum, it's a forced shift, it's clunky, loud, and doesn't feel right.

Best way to avoid it is know at what speed it will shift to 2nd and stay on either side of that shift point. You can also lock it out in 1st, or 2nd, if you'll be crawling along stop-and-go.

 

[KMPrengerMO]

This probably isn't related to the torque converter issues mentioned above.

...

I agree.

I just felt it was worth posting on this site and this seemed relevant. I intended to post it to a torque converter thread also.