The clutch doesn't determine capability. That's the fan, fan shroud, and radiator.
Having said that, the automatic and manual transmission early 4.0L fan clutches are not the same. I suspect the auto one clutches at a lower temperature. But if you're overheating, that won't help. I guarantee the manual one won't stay off at overheating temperatures if it is working properly.
If you're having overheating problems, check the radiator is not plugged (feel for cool spots), make sure you have the "full" fan shroud and that the fan clutch works. If everything is fine, put in the 2row 4.0L radiator if you have the 1row (you'll need a fan shroud from the junkyard or your hood won't close).