Toyota Repair: PROBLEM WITH 4 WHEEL DRIVE, relay switch, add auto

Question
I have a 1995 6 cylinder 4 wheel drive T100. I can't get my truck to go into 4 wheel drive when I pull the lever down. Sometimes if I accidently leave the lever down and several days later go to start it and go to work the dash board will indicate it is in 4 wheel drive. Then I drive it to work and it is working. Then when I take it out of 4 wheel drive it goes out immediately. Then I go through the same scenerio again. Pull the lever nothing happens, then several days later it will work etc.. etc....

Answer
Is it auto trans? Does it have an ADD?
{Auto Disconnecting Differential}

You may have a acuator problem.Its on the side of the front diff. Bad actuator,bad relay , switch etc.

When you shift the transfer into 4wd the switch in the transfer tells the front diff vsv to operate and apply vaccuum to the acuator, then it "shifts" the front axle into 4WD.
Then it lights the light when it confirms its in 4wd.



You can look under and see if it moves when you have someone shift shift to 4WD.
{in park, dont get run over}

You can get the diagrams at www.techinfo.toyota.com

Mike