Crunching when changing gears on a pajero - 1992 Mitsubishi Pajero

Manual transmission? yeah, oil could have low for to long. If it grinds in all gears, synchronizers are gone. Adding oil won't help.

Check the oil level of the gearbox, if level is low or oil is too thin will cause it to crunch. put an 80w90 gear oil into it if needs fill or change/ also check the clutch is fully disengaged. maybe clutch hydraulics have air in the system, this will reduce the travel of the clutch fork and not fully disengage the clutch. to see if its the clutch hydraulics select 1st gear push in the clutch and start the engine, if it starts to creep forward check out the hydraulics. if all this ok, prob be the synchro rings internal in the gearbox