depends on the year Montero and the motor it is off of. If the mount is the same, you will just have to switch pulleys to match the v belts on your truck, and maybe change the plug on the harness, although your truck should match the new alternator. A starquest (Starion / Conquest) alternator is another choice -75 to 100 amp depending on year and model. There is also a Mitsubishi van alternator that is a direct bolt in - 75 amp minimum.