1994 mitsubishi montero squeaks..?

it sounds more to me like your shocks might be what causing it. speaking your truck is 14 years old, but like the master tech said some things don't have a grease fitting so you have no choice but to replace some of the bushings and bearings. but usually if its a bearing wheel bearing it makes a hell of a noise going down the road slowly picking up and slowing down as you drive. I'll say try the shocks.