if you blew up your TH400 (the only non-OD automatic offered 88+), there is only one answer. SM465 manual. if you break that thing, you need to look into getting a medium duty truck (1 1/2 ton or larger
) your brother didnt just kill your trans with this one occasion of heavy towing, it has been going down hill for a while, and my guess is you or the previous owner have neglected proper maintnance on the trans. there's a reason they put TH400s behind 454s, they're tough as nails as far as automatics go.