thunderbird transmission/ exhaust overheating

I have a 94 thunderbird with the 4.6L v8 and AODE automatic transmission and stock exhaust. Within the past few days I have noticed that possibly the transmission is overheating when driving. The car runs fine, shifts how it always has and goes into every gear. There is a Hypertech chip on the engine computer that speeds up the transmission pump so it shifts in between gears quicker. The fluid and filter on the transmission was changed about 3,000 miles ago and the fluid is still clean and shows no signs of burning or transmission wear. While driving it last week I was coming to a complete stop and heard an odd clunk noise from the transmission underbody area but the car drove fine after that. I have not noticed anything wrong with the drivability of the car and it runs good including when I drive it hard. But whenever I do drive it more than about 5 miles, no matter the driving condition, the carpeting around the shifter area, the actual shifter and surroundings get excessively hot and when I get out of the car I feel the heat radiating from underneath the car. No check engine lights come on and no error codes show up on a reader. I have not dropped the pan down to see if there are any irregularities, it is very possible that the filter dropped down into the pan but that would not explain the heat. The heat could also be coming from the exhaust system, i.e. the catalytic converter and there are no exhaust leaks.
Any ideas would be much appreciated. thanks.

Since its been so hot up here in the NW latetly. Maybe its just the ambient temps around us? :) If anything, the exhaust would seem to be more of a possibility for these temps. Maybe its becoming restricted? Maybe theres a shield missing around one of the cat. converters? Trans. temps should stay fairly focused within the transmission. Transmissions can get really hot, but thats usually from a torque converter malfunction (impeller rubs on turbine) or clutch slipping badly!

If someone had an infered temp gun, maybe they could see whats up?

Try driving it at night and then look under the car to see if the cat. converters or and part of the exhaust system is glowing from heat.

that sounds great, i'll check out the infrared temp guns - hopefully they are easy to come by.
If it is the cat converter then im hoping its not too difficult to track the cat and pipe assembly down.

that sounds great, i'll check out the infrared temp guns - hopefully they are easy to come by.
If it is the cat converter then im hoping its not too difficult to track the cat and pipe assembly down.

RockAuto.com has them, but they are $$$$$$