99 Toyota Wont Go In 4WD

99 Toyota Tacoma 4wd ext cab, manual trany,SR5, 3.4 v6, both shifters on the floor, and has almost 200K.


Wont go in 4wd. When in 4H or 4L the "RR diff lock" light blinks. I looked under it yesterday and only thing I found that needed replaced as far as hoses is the vacuum hose thats on top the transfercase under the shifter going to the passenger side of the trany. Both ends were dry rotting. Replaced that and still doesnt engage to 4wd. 4wd last worked in August but all sudden just stopped engaging. Any ideas others and how to check it?

 

Get whole truck off ground and put it in 4H. Then check if the front shaft spins when giving it gas. If it does, then your front diff or actuator is the problem. If it doesn't spin, then the problem is your case somehow. After that, try listening for engagement when you shift between 4h and 2h. That'll help focus your problem area.

 

Any updates?

 

Even easier way is to just jack up the front end with the parking brake set. In 2WD, you should be able to spin the front driveshaft, in 4WD you should not. If you cannot spin the driveshaft in 4WD, the problem is with the ADD. If you can spin it, then the problem is with the t-case.

 

Going to check it today. So theres not really a external actuator on this? According to all parts sites all im getting is a transfercase switch.