I have noticed some funky shifting, I have a 2022 gmc at4 2500hd with 27,000 miles on it. No upgrades to tires or lift I bought it with 7000 miles on it. The brakes/rotors were toast when I bought it. It’s down shifted really hard when coming off the freeway to a stop. Almost like it skipped a couple gears. Wondering if anyone else has experienced this. Also I have had my screen lock up as well as volume controls lights flashing at weird times.
Transmission hard down shift
- Thread starter 11freetwo
- Start date
Did you buy it from a gm dealer? My '22 3500 duramax had a campaign to reprogram the tcm. Dealer did it when I had them do the idle kill timer programed out, with less than 600 miles.
I did, probably should take it in? It doesn’t do it all the time but I have felt it more than once.
You could call with your vin and ask dealer if it's been done. I would have thought dealer would have done it before being resold.
I didn't have any issues, so I don't know if the update would cure what you are describing.
I didn't have any issues, so I don't know if the update would cure what you are describing.
Bronc davis
New member
I had the same issue. It's the valve body in the transmission. It down shifted so hard while pulling a 30' gooseneck loaded down it shelled the rear end. Had to have rear end rebuilt twice and new valve body in transmission. And the rearwnd just shelled again. I'm trying to get gm to do a buy back.
Dam that does not sound good.
jgaestel
New member
I went from a 2020 1500 Denali to a 2023 Sierra 2500 AT4. I am very sorry I did. My thoughts were that the fuel tank was bigger and could tow more, but after driving it, I feel the Denali handled my trailer better. The Ranchos and not as good in my opinion. But I digress. For me, I too am experiencing the lost of my truck due to parts delays. I was coming home with my small trailer and had two hard shifts, bang, bang. Then I got the in reduced power mode. I have only had the truck less than a month and I get this issue with only 42000 miles on the truck. As most of you all, the dealer is telling me it maybe a 4 month wait to get a valve body. Completely unacceptable. I bought the truck through CarMax and working with them to buy it back due to the long delay in fixing the truck. What a cluster. Any suggestions I would appreciate it. Thanks
jgaestel
New member
Just checking in to give an update on my transmission parts delay. I called the parts department to check on what was ordered. The parts guy verified the valve body was ordered but when it was to come in was a guess. Seems the orders are filled at random and can only be tracked once shipped. Then he said wait a minute...he found a new transmission in stock. He was to put hands on to verify it was actually there and not allocated. The next day I called and the transmission was available. He put a hold on it and submitted to GM for approval to replace the whole transmission due to the infinite delay on the valve body. Well the approval did come through and as I write this post the truck is getting a new transmission. What a deal. Now the question is do I keep the truck or sell it back to CarMax and buy another truck? Keep it or not. Any thoughts on the new transmission. I am inclined to keep the truck, 42k miles and new trans. What do you all think?
jgaestel
New member
Thanks for the input. I will be picking up the truck next Tuesday and give it a drive to see how it does.
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