Joined this sub, solely for this topic. I have a 23 trailboss with the 3.0 and the 10-speed. One day I had a random hard downshift, I figured I just confused the transmission with accelerating and then taking my foot off the pedal. One week later, my truck acted like a 16-year-old learning how to drive a stick shift. CEL came on and limp mode. The dealer said it was the valve body and it'll be a 3 month wait. Luckily, a classic Chevy dealer had the part (no idea why) and I was back on the road in 5 days. The part number they put in is 24065353. I'm hoping this is a redesigned part and not the same part that's gonna fail again at 20k.
To make matters worse, 2 weeks after getting my truck back, I had another random hard shift. It's when I'm lightly accelerating, and then let off the gas. It wasn't extreme, but you can definitely feel it shift. Has anyone else experienced random harder-than-normal shifting, or had their replacement valve body fail again? I can't even enjoy any new truck because I'm just waiting for the transmission to fail again.