The automatic that came in them is the same as a Jeep AW4 behind the 4.0 liters. Its called the A340 in the Toyota, its plenty stout for a 4 cyl.
IMO, they sap too much power, and the other issue is that they don't accept the gear driven transfer cases, they have an integral chain drive case. You need a spendy adapter from inchworm to get the good cases on there.
I know since the adapters came out, there have been people who've had issues with starving the converter for fluid on steep climbs.
I know of at least one person running a C4 trans with a toyota bellhousing. But he has the power out of his 22RTE to light up his tires, too.