Transmission Cooler

I bought a 2002 Explorer which has an 5 speed automatic transmission with no dipstick. Ford say's it's a sealed transmission that does not need to be serviced for 150,000 miles. It came with a trailer hitch from the factory. I didn't see a transmission cooler in front of the radiator like other Explorers had in previous years. Can someone tell me if one can be added to this vehicle? Was there a reason Ford did not install one for this model & year? I looked at other 2002's and did not see a trans cooler on these either.

Thanks
Jim