4x4 worked perfect last month. now when i hit 4hi or 4lo i hear what i think is the actuator engaging the front diff but there is no power to the front wheels. and the light blinks continuously in 4hi or 4lo but will go back to 2hi no problem. tried changing it in neutral, park, while rolling, in reverse, nothing helps. can anyone help me out? i wanna try out my new tires and winter is fast approaching! thanks!