First, congrats on the 8.2K half ton...a very rare truck
7 lugs to differentiate from a 'normal half ton' (6 lugs) and a 3/4 ton (8 lugs)
You do need to find the root cause and fix that
250*F at the side of the pan says inside the tranny has the ATF much higher and
most likely why it set the code.
Again, suggest you find the root cause.
Maybe partial blockage of the run to the main radiator, or to the external ATF
cooler (they should be series)
Gotta find these things based on this indicator of potential failure out in the
boonies...