89 montero fsm on mitsubishilinks.com (iirc).

The spring pin is accessible from the bottom pan, and can be repaired in the truck. If it's the syncro pair, you have to tear down the tranny. It's not real hard, but you may need some special tools. I managed with normal hand tools to rebuild a similar tranny (mazda R in a Navaho).

Not responsible for advice not taken...