Yes, you can, they are the same transmission, the final drive may be a bit different but it's all the same, you will have to use the engine mounts from the '85 as there were some minor differences in mounts, BUT the mount points are the same.
Yes
Yes, with enough money anything is possible.
Yes, it would be a lot of work, though.
Yes, you'd have to find the stock automatic transmission for your year and engine size, the stock automatic brake pedal assembly, and miscellaneous small things like transmission fluid, the transmission dipstick tube, linkages, etc.
A parts car like yours with an automatic transmission.
the maintance manual tells you to adjust the bands each time you change the transmission filter, but does not tell you how. the bands should be on inside of pan.
automatic transmission fluid in a pajero io
It may be possible to have a shop to do it for around $250-$1200
Can you change a automatic to a 5 speed Honda Accord 1990
How Do I Change My Automatic Transmission Filter?www.2carpros.com/how_to/transmission_service.htm
If your transmission is manual, you will have to change gear. If it is automatic, you won't.
You can change a manual transmission to an automatic. It can cost upwards of 3,000 dollars to do this for a Volkswagen Polo.