Since we're on the topic of upgraded valve bodies, my truck got hung on 4th gear when coming to a full stop but not after going through 57 1/4 seconds of cold sweats and nerving panics.
At first, I didn’t notice, but when I tried to get moving, it felt like it was in neutral. Confused, I shifted to N, dropped it back to D, heard the transmission engage normally, but still nothing. Trying to stay sane while imagining every potential 10R140 problem going through my mind at an astronomical speed, I took a deep breath and told myself, chill and think thoroughly. To my surprise, it moved, but felt sluggish—like trying to take off in a high gear with too tall of a ratio but again... I wasn't fully aware of what was happening since I've got traffic behind me, all while trying to cross an intersection safely.
I make it across the intersection, still confused, until I glanced at the gear indicator and saw it was in 4, even though I was only going 3 MPH. Then it all clicked -- it's been on 4 the entire time, of course things are now starting to add up but the question is why? Regardless, I pulled over onto the shoulder and noticed how ths time, the transmission does drop from 4 to 2, then 1, and I came to a complete stop. I knew this time I’d be able to accelerate, she's back with me, and I head to my destination without any repercussions.
Totally puzzled, I called my mechanic, also confused, has me come by to scan for any codes. To our surprise—nothing, zero, nada. We then phoned a local transmission guru, but even he was stumped since he hasn’t worked much with the 10R. He suggested the issue might be a stuck valve body, something he’s seen often with the 6R140, but shocked at the fact that it didn't trigger any codes.
My mechanic mentioned he’d contact another transmission expert out of Pennsylvania, though I can’t recall the company’s name—it wasn’t Suncoast or NextGen. I’m thinking I might get more answers from the forums than from him, and I was a bit surprised that even after six years of the 10R being around, there’s still so little known about it.
@JTredway as mentioned in another dicussion between us, I do cycle through the drive modes quite often, could this potentially be the case where the computer didn't fully come back to its mode. I wish I could recall the sequence of modes I went through prior to this strange behavior but it may be myself, that could be confusing the brain? Just throwing that out there now, since I don't recall seeing this discussed previously. Lastly, I don't even recall what drive mode I was in but if I had to guess, it was Tow Haul.