I think the only way to get the fluid out of the torque converter is have the transmission flushed, normally just changing it is enough, the only other thing you could do but it's a bit of a pain is change the fluid again after a few hundred miles so the old stuff in the torque converter has been mixed with the new but I wouldn't bother. I don't know why they never fitted a drain plug on the transmission pan it would be much easier, although you can buy an after market one with a plug. When I changed my fluid I put a thin plastic pipe down the transmission filler tube and used a suction pump to remove most of the fluid, it takes longer but when you remove the pan there not much oil to spill.
Don't forget to use the correct fluid which for a 96 is stated to be Dexron III spec. it says 5 quarts (4.73 Ltrs) if not flushing the torque converter which seemed about right when I did mine.