5 speed Dakota tranny?

I have what I believe is an AX-15 in a 97 Ram Full size.
Truck has 200K.

Trans is by no means a slick shifting, powershift type of transmission, but I attribute that more to the age, then the transmission. 1-2 is not happy when cold, and 2-3 is getting grumpy too. I run full synthetic.

I think my transmission gripes are age related.
I do know that in full size truck with roughly 30 tall tires, and the OD + 3.55 rear gears, the truck feels like it needs an extra gear. It is VASTLY improved to a 727 or non OD 4 speed, but by modern standards, 65 is the perfect speed, anything more puts the truck into more RPM then what it wants to be at. But 65 "happy spot" is with 30" tall tires, and the OD. A car with 25-28 inch tall tires, would have a happy spot of 55-60.

For my setup to be truly comfortable in a car, I think a 3.23 gear would be needed, to keep the RPM down compared to the 3.55 in the truck, with 30" tall tires.

I think an OD vehicle, should be be able to run a deeper gear and stay in the "happy range". Perhaps this particular unit does not have a very deep OD gear.