Have you ever considered swapping to a 4L80e?
A STOCK 4L80e transmission is pretty dang tough in a 3/4 ton+ work truck or van towing and getting abused 6-7 days a week. In a light 1500 chassis, that transmission literally laughs at you when you push the metal-to-the-metal. Not joking either.
I know the 4L60e, 4L65/70, etc. al. can and do get built to handle high HP and abuse, but that's usually on lighter vehicles like cars, albeit at a pretty dang hefty price because literally everything internally gets replaced, then you still manage to break the next weak link. SMH.
My logic has always been, "I simply can't afford a 4L60e". Just a thought...
I hope things get sorted out, regardless. BTW praying for your health Brother.