On ih8mud.com there's a thread from someone who put a 3B into a 4-Runner and it has been burning through transmissions.
The 3B originally shipped with H series trannies AFAIK. H41, H42 are 4 speeds, H55 is 5 speed. The H series are pretty heavy-duty next to the truck trannies.
If I had a 3B/H55f sitting around, I'd be looking more for a FJ-40 to put it into, but I'm sure it *could* be done into a pickup. Seems like it'd work just fine in a pickup, and last a long time, but it also seems like overkill.
1991 4x4 Pickup, 2LT-E, R150f
1976 HJ-45 Pickup (needs restoration)
"Who's behind the curtain anyway? Who pulls the levers and tells the lies?"
--Five Iron Frenzy