I have a 2.7L with a 5 speed automatic, and have experienced random overheating issues. As my drivetrain is squeezed into a 93 2 door, there is a big difference between vehicles, but my solution has been an oil cooler for the transmission, and a good 3000 cu.ft. fan replacing the auxiliary fan. I route the transmission oil through the oil cooler, then the radiator and back together transmission. That way I am not over cooling the transmission, but still taking a load off the radiator. As that wasn't sufficient when crawling, I replaced the auxiliary fan (in my case the only fan) with a 3000 cu.ft. fan. Haven't had problems with overheating since.
The solution may be as simple as replacing the fan clutch, or a good tune up.
Enjoy your new project.