One thing that you must do is to verify that you have fluid flow through the transmission fluid cooler that is located inside the radiator.
With all the little pieces that you mention throughout the transmission are likely to also have gotten into the transmission fluid cooler.
This can block the flow of fluid through the cooler, causing your transmission to overheat.
If the transmission fluid cooler inside the radiator is blocked, the repair is to replace the radiator, in other words, you cannot repair that part.
One could install a auxillary transmission fluid cooler in front of the radiator, but you will need to get a big one if you are using it to replace the one in the radiator.
In other words, you could connect the transmission fluid cooler lines to the auxillary cooler INSTEAD of the radiator.
If your vehicle has the factory installed auxillary transmission cooler, it will NOT be big enough to replace the in-radiator cooler.