Chuck...he's a GT aka 3.29 gear ratio. His speeds etc sound about right for 4th TCC locked.
Easy way to test TCC is holding your foot steady on the throttle at 70mph once it does that secondary drop down, Tap the brake pedal with your left, just enough to kick on the light. You should see the rpm jump 200-500 and then go back down a moment after the foot is removed from the brake pedal. That's the TCC disengaging and reengaging.
To tell if you get 4th.. simply pull the gear selector to 3rd and see the rpm go up close to 1,000rpm.
When you are doing 70mph and the car is sitting at about 2100-2300, if you stuff it to the floor, what rpm does it go to immediately?