Toyota Repair: 97 4Runner wont shift into 4wd, vacuum pipes, vacuum hose

Question
Hi Ted,

I have a 1997 4Runner Limited V6 Auto 4WD. When I push the button on the High/Low range shift lever to go into 4WD I can hear the electronic solenoid on the transfer case "click". However, the 4WD does not engage and the dash light does not come on.  The truck has 98,000 miles.  Will this be an expensive repair?

Thanks,
Mike  

Answer
Although the transfer case engages to lock both differentials together the front differential does not lock to provide front wheel drive, this could be because the front ADD(automotic disconnect differential) actuator is not working, have it checked for that, sometimes the vacuum hose connections fall off or the vacuum pipes on the actuator get clogged up.