I have a 2023 Denali 2500 diesel with the Allison 10 speed transmission with 49000 miles. The other week, while accelerating on the highway, I truck started jerking, check engine light came on and power was reduced. I limped back to the dealer and was told it was a software issue with the fixed. They said to keep it local to try it out but 35 miles later, it happens again. This time they said it the transmission valve assembly. Not a bad thing, all under warranty but now they said the part is back ordered and no idea when it will be in. Reading some other posts and it seems it can be months. A friend helped me and found a unit at a dealer in Scottsdale Arizona which I shared with my service adviser, she said they can’t do that. They are getting me a loaner truck but are not happy that I drive about 4000 miles a month. Any advice on how to proceed or am I stuck in the waiting room? I even offer to buy the part myself, $1100.00 and have them install it but that didn’t get a positve response.