You can use the TV cable from your bad transmission if it is works smoothly.
The '89 transmission uses the computer to actuate the ground in the torque converter lock up solenoid (usually terminal "D"). You might have to modify the wiring to get it to lockup.
As mentioned earlier, you will need to use your old governor or change the weights on the current one. The input shaft on the '89 has more splines so you will need a later torque converter. You should get at a minimum, a heavy duty RV diesel torque converter. Finally, depending on who did the transmission rebuild, you might also want to install a TRANSGO shift kit to improve shifting and oil pressure.