Transmission goes to limp mode when coming to a stop

Let's scan the vehicle for codes because I suspect you have codes that will point us in the right direction.

However, this 42LE transmission did have valve body issues that would fit what this is doing. Basically when a solenoid would stick it will cause limp mode because the computer is seeing something it shouldn't do. Then when you remove power from the solenoids they reset and it drives fine.

The sudden stopping will cause valves to move quickly and this could be causing them to stick.

If we don't have codes then I have some other ideas but clearly the codes will help us figure this out. Most parts stores can pull them if you don't have a scan tool.

https://www.2carpros.com/articles/reduced-power-limp-mode

Sounds great. Let us know if you need more help when you get the code and we can go from there. If not, let us know what it was whenever you get it repaired. Thanks