I purchased a used 2023 GMC Sierra 2500 4x4 in July of this year. 50,000 miles on it. I drove it for 5000 miles and then all of the sudden, it went into reduced power mode. Read the codes and hometown dealership informed me it needs a new automatic transmission valve body. This was in August 2024. They told me the part is on backorder with not eta. I was told to disconnect the negative leads on both batteries; wait about ten minutes; then reconnect to reset the computer. That worked the first 12 times. I checked today, the part remains on backorder and they have another vehicle needing the same part. It’s very frustrating trying to get to work when can only do 45 mph on major highway. And now it sounds and feels like the transmission and power tran is about to fall out. No offer for a rental or loaner. Come on GM get it together.
