i ran a 42 inch tsl on my 85 far a few weeks-in the hammers, and i beat it, and rolled it seven times,,,,the axle is about all that survived
its just like anything else toyota, if you hammer it, and abuse it, it will fail with 31s or 40s, think while you wheel, and plan lines, yuo should be fine, although i would recomend knuckle gussets for good measure
