Trimatic Gear Selection

Hey all,
Is there any way to tell if a trimatic is selecting gears properly? I have recently installed a commodore trimatic into my torana, and had to modify the commodore shifter to make it fit in the old manual shifter hole. Now I am unsure if the shifter is engaging completely or not. What method do people use when installing a new shifter, such as a cable shifter to make sure it is all selecting properly? The last thing I want is to burn out the new tranny due to incorrect linkage adjustments.
Cheers