I have a 97, 4 runner. It is a 4 cylinder with 160,000 miles. A few months ago the 4x4 was working great. I went to use the 4x4 recently and it did not engage. My 4runner has a manual shift system. I engaged the manual shift and could feel the car adjust. However, the light in the dash did not come on as normal. Also, the front wheels did not engage. I only left the car in 4x4 for a moment, but it was obvious that there seemed to be a conflict between the front and rear. I had a friend tell me it might be the vacuum and/or the actuator? What do you think? Is this something that can be repaired at home?