I took the battery out and seeing if the actuator is working. It seems to pull the cable when engaged in 4hi. It does not pull it far enough back to engage the front axle. If I put it in 4hi, then help it pull the cable back to engaged position, it will stay there. It does not seem like it is pulling it back far enough. Is this the actuator that may be bad? I have already replaced the valve on the transfer case itself.

 

Remove the vacuum line from the actuator, put a vacuum gauge on the vacuum line, select 4WD HI, engine at idle, trans in park. Gauge should show manifold vacuum, (approx 16"-19"Hg.) Shut the engine off and vacuum should hold. If not, there's a leak somewhere. Either the vacuum switch on the transfer case is leaking internally, the vacuum line from the vacuum switch to the actuator is leaking, (cracked line etc), the diaphragm is leaking on the actuator, or a leak in the vacuum source line.

 

Figured out the problem. I checked vacuum at the actuator and only had around 5. I checked it coming into the vacuum switch on the transfer case and had around 16. I then took the line off going to the actuator to see what I had coming out of the switch and only read 5 on the gauge. Replaced the switch for the 2nd time, works like it should. It definitely helps to have a vacuum gauge. I was hoping not to have to replace the vacuum line from the switch to the actuator. It looks to be a pain to route that line up to the front.

 

Thanks for posting back with the "fix".