2022 transmission issues <1k miles

NewtoGMC · Jan 4, 2022

Hello all, new to GMC after tiring of my 13’ F150 eco boost lack of towing power. I drove a new 2022 AT4 6” bed off the lot two weeks ago. Drove it 4 hours to my hunting land in NY and put it through some light snow and mud in 4x4 high. On the highway drive home the truck started hard shifting between 50-70 mph. Didn’t think much of it with new 10 speed transmission and break in period, however after returning home and driving daughter to school the next day the truck didn’t want to shift out of low gears. Experienced shuttering, high revving and general transmission slipping. Felt like I was in 4x4 low until I got past 40 mph. Immediately had it towed to dealership and already getting the run around. Anybody else have issues with less than 1k miles?? Dealership is running diagnostics but is this a software issue or just bad luck on a brand new transmission?? Thanks! Love the truck otherwise!!

Pb82 Ronin · Jan 5, 2022

Just hit 1K miles...luckily no issues yet. Although I haven't used 4x4 modes yet...making me wonder if I should test them out.

NewtoGMC · Jan 5, 2022

Update: dealership ran diagnostics and is concerned the truck left the factory with the incorrect transmission fluid. They are doing a flush but my guess is they will need to replace the transmission. More to follow…

Kevpak24 · Mar 4, 2022

Similar story - Coming from a 13' F150 Ecoboost. Have had my AT4 since December. Almost since new it has had a bad rattle at low speeds. If your going 5-20 mph and let off the gas it sounds like a baseball card in your bicycle spokes or even a jake brake. Just got it back from my dealer earlier this week. They drained the tranny fluid and found filings. Ended up replacing the planetary differential - had a gear tooth chewed up. All good now. 3500 miles - Haven't towed anything with it yet. Just glad they could get parts to fix it.

CsiskTB · Apr 19, 2022

Not a AT4 owner but I am a 2022 TrailBoss owner. Bought TB early Feb 2022, took it in the shop due to it going in Limp Mode at 800 miles. They had the truck for 39 days, changed the speed sensor, harness, and some valve. Finally received it back from shop with issues resolved. Hit 1400 miles and issues re-appeared. Took it to another Chevy shop for diagnostic. Took them 4 days to say transmission is the issue and that they have been seeing this same issue with a lot of Silverado/Sierra 1500s, Tahoe, and Cameros. If you haven't thought about it, you might could claim it as a lemon vehicle. Im going through the process with BBB.

chevydeth · Apr 8, 2023

My 2022 LM2 AT4 is starting to have issues. Started off early on with a hesitation or shudder during light acceleration from a stop at about 1k miles. It felt similar as my old 8L90 that had torque converter issues like the rest of the 8 speeds out there. I was told it is still breaking in and its no issue. Yesterday it threw DTC codes P0700 (Transmission Control System - MIL Request) & P1789 doing a highway cruise at 60 mph under little to no load. Anyone else have similar issues?

TX_Critter · Apr 12, 2023

I had an issue with mine in the first 2k miles or so, I was 300 miles from home and it went into some sort of limp mode where I couldn’t access the bigger gears so had to limp it home at 55mph. Dealership picked it up and had it a couple weeks but all has been good since and I am over 12k now. Was told it was a bad input rpm sensor…

Here’s the onstar diagnostic email showing the codes it threw: