Not sure if GL5 will work but in case it doesn't, you should be able to get GL4 fluid from a local Mitsu dealership.

Off Roader
98 Montero with the Winter Package
89 Montero minty clean and reserved for overlanding trips or Cars and Coffee events
96SR (3.15:1 xcase, 35's) gone to the rust gods
96SR Build Up Thread
Old web page
Old web page