I missed out on one in an '82 K10 a few years back...I agreed to buy the whole truck for 500 bucks ,by the time I went to the bank and returned,the truck had been put in the crusher..
We had a few Dodge B100 telephone co. vans at the junkyard I worked at,they had the same overdrive tranny--and I drove one a few times on parts deliveries,and I liked the tranny,I thought they were geared just like a "three on the tree" three speed,in the first three hears,only difference was they had an overdive in 4th gear..not sure of their durability,but these vans had a 225 slant six and both had well over 200K on them,and both were heavily loaded down with parts racks,tools and wire,and we beat the snot out of them and never had anything go bad with the tranny's..we blew a few clutches though..I think a stock 6.2 would have a hard time breaking one,as long as you didn't go doing burnouts or try pulling stumps,etc..