1996 Mitsubishi Diamante Transmission drain.

There is a drain plug at lower part of the oil pan and another at lowest part of differential housing. However using these drain plugs alone would only allow you to replace about 40% of the fluid. Removing the oil pan would allow you to replace 70% of the fluid. The filter should be replaced if the fluid is dirty.
When re-tightening the oil pan bolts, do not over-tighten as it can result in oil leaks as the gasket would be crushed.