Shifting Hard and Stutter

[Bigfishbobby]

I just bought a new 22 Trail Boss 6.2. I believe it is the refreshed version. I’ve noticed at times it seems to shift hard into 3rd or 4th gear (around 25 mph or so) and seems to kind of act like it’s struggling when I’m doing about 35 mph and just maintaining speeds. It’s very faint but I swear I can feel it. I had a corvette that had a torque converter replaced and it kind of feels like that, but the vette was predictable and consistent. This is somewhat intermittent and I’m not sure if it’s normal, if I should be patient during the first 500 miles (I’m at 300 or so), or if I should have it checked out. I’ve played with the throttle and it doesn’t seem to be engine related as it doesn’t happen when you get on it a little at all. It’s only noticeable in the first few gear changes and at lower speeds when maintaining speed. As smooth as this thing generally rides, I am struggling to believe this is normal. Any insight is appreciated.

 

[Bigfishbobby]

Kinda got buried because it’s my first post and my account didn’t get verified for a couple days. I’m bumping this hoping to get more eyes on it.

 

[TexasPat]

Hmm, does it feel like it’s “shaking” (the vibration like a wheel is out of balance, but across the whole truck)?

 

[Bigfishbobby]

The shifting part seems hit or miss but it just kind of slows down then surges. The shuttering is minor but feels like when you shift into too high of a gear for your speed and then the vehicle has a bogged down feel trying to go. Definitely different than a tire out of balance.

 

[TexasPat]

That’s weird. I have a 22 refresh (one way to tell for sure if it’s a refresh is if you have the center console electronic shifter, the black hood scoop, or the front end that has the turn signal in the DRL if it’s an LT) and I had a vibration/shaking feeling and some weird shifting. It started at 300 miles right after a “service transmission” warning popped up on the dash, but then went away. The shaking/shifting was intermittent, but enough to bug me. I took it to a dealer and they figured out it was the shifter control module. Apparently it was faulty and was causing a small/intermittent interruption in the information that the ECM was trying to send to the TCM, since it sits between the two (or at least that’s how it was explained to me), resulting in the shake/shift issues.

I know the dealer can be a hassle, but it may be worth taking it in and having them take a look at it if it continues. Like you said, it could just be part of it “learning” how you drive, and part of the break-in process.

 

[Bigfishbobby]

That’s weird. I have a 22 refresh (one way to tell for sure if it’s a refresh is if you have the center console electronic shifter, the black hood scoop, or the front end that has the turn signal in the DRL if it’s an LT) and I had a vibration/shaking feeling and some weird shifting. It started at 300 miles right after a “service transmission” warning popped up on the dash, but then went away. The shaking/shifting was intermittent, but enough to bug me. I took it to a dealer and they figured out it was the shifter control module. Apparently it was faulty and was causing a small/intermittent interruption in the information that the ECM was trying to send to the TCM, since it sits between the two (or at least that’s how it was explained to me), resulting in the shake/shift issues.

I know the dealer can be a hassle, but it may be worth taking it in and having them take a look at it if it continues. Like you said, it could just be part of it “learning” how you drive, and part of the break-in process.

Thankfully I haven’t had any lights or real problems, just a feeling that something isn’t quite right. Mentally I’ve been hoping that it will work itself out. I called the local dealer and spoke to a service advisor who explained that hard shifting and even clunking noises are normal. Obviously, he wasn’t a ton of help.

 

[TexasPat]

Yeah that is definitely a positive! You are pretty early into the break-in process, so there definitely is still time for it to work itself out! If I recall correctly, the initial break-in is in the first 500 miles, and it is considered “fully” broken in after a few thousand miles…but personally I don’t believe a truck can be broken in until you get it buried to the frame in the mud.

 

[johnnyh]

I’ve also got a 6.2 LT refresh and noticed the same thing under 30mph hard shifting/kinda vibration-y throughout the truck.. I did buy a CAI and thought maybe it was that because after I put it on the truck just felt more sluggish.. I was going to put the stock back on and test the difference but kinda just ignored the problem. It’s been constant though since 100 miles into now 4K miles so breaking it in didn’t seem to fix it.. no engine lights knock on wood, just upgraded to a cat back exhaust figured maybe it just needed to breath a little more.. still an issue though following.

 

[Bigfishbobby]

Well, here’s an update. Dropped it off and the dealer supposedly took it out with a computer hooked up. They called and told me everything is normal. I’ve never had a bad experience with Chevy, but a 60k+ truck shouldn’t shudder, thump and shift erratically. At this point I’m hoping a tree falls on it, a meteor falls from the sky onto it, or Chevy gives me a solution. The tree is the odds on favorite but I’ll most likely trade it in and take a bath on it, and never buy another Chevy. I’m extremely disappointed because I really like the truck otherwise.

 

[johnnyh]

I saw this while researching the issue, it’s exactly for the rough shifting haven’t tried calling yet but probably wouldn’t hurt. Even if you don’t have a refresh.

 

[Bigfishbobby]

Thanks. They say there are no bulletins for my VIN. I actually showed them that one. They said they did a software update but it did nothing to solve the problem if they did.

 

[ChevyChic85]

I just bought a new 22 Trail Boss 6.2. I believe it is the refreshed version. I’ve noticed at times it seems to shift hard into 3rd or 4th gear (around 25 mph or so) and seems to kind of act like it’s struggling when I’m doing about 35 mph and just maintaining speeds. It’s very faint but I swear I can feel it. I had a corvette that had a torque converter replaced and it kind of feels like that, but the vette was predictable and consistent. This is somewhat intermittent and I’m not sure if it’s normal, if I should be patient during the first 500 miles (I’m at 300 or so), or if I should have it checked out. I’ve played with the throttle and it doesn’t seem to be engine related as it doesn’t happen when you get on it a little at all. It’s only noticeable in the first few gear changes and at lower speeds when maintaining speed. As smooth as this thing generally rides, I am struggling to believe this is normal. Any insight is appreciated.

I have a 2022 Trailboss with the 2.7 just under 18k miles on it ive had it in and out of the dealership since November, same issue as you have plus many more things at 11k #4 fuel inject blew what fun that was......several times ive lost the ability to drive after making a complete stop meaning the needle didnt move for rpms or mph in drive but reverse no problem.......replacing sensors, front camera module, and fluid for the torque converter next........its not normal at all its wearing out the parts in your beautiful ride i am disappointed in GM and their LACK of care they have shown towards my concerns anyways

 

[scamacho]

Any remedy yet? Same issue. I’ve got 6.2l with DFM. 10speed. Dealer already changed out and reprogrammed transmission module but didn’t work.

 

[Kyle91]

My 2023 has 8000km on it with the 10-speed trans and it is already going in to have the torque converter replaced next week

 

[Bear76]

Recently traded in a 22 Dually GMC for the Trail Boss.

Had a similar issue with the 22 that you are describing.

In one particular part of the daily drive, there is a slight upgrade in a 50mph zone. Trans would be in 10th starting the 1/2mile grade and would attempt a downshift to 9th while under a 100% engine load condition. 9 times out of 10 it would initiate the gear change then seem to be indecisive and do the whole shudder/shake thing. If I mashed the pedal down it would force the tranny into 9th. If I didn’t use cruise control, the tranny would downshift normally. Dealer could never replicate.

It only did this under those specific conditions and with cruise on.

I found the hassle free “fix” was to set the cruise at either 52mph for the climb or 48mph to force the tranny to shift to 9th prior to climb to remain in the proper power band.

All the dealer could offer was a reflash and tranny fluid swap out for the fix. I think you may be on the right path of engine load vs gear selection and you may be operating right on the boundary of what the tranny WANTS to do versus what the ECM THINKS it should do.