well I dont know about running it in a sammy, but I run a auto in my tracker with 31x10.5's and a rear mini spool with alot of daily driving. I upgraded from the 4.62 gearing in the diff to the 5.12's because it was alittle weak around 65mph but with the 5.12's it was like running a stock tracker.
I would think a auto would be ok in a sammy as long as you upgraded the 3.73's in the diffs. I have been thinking of moving 1.6, and auto into my sammy as well.