vacuum actuator help

Im trying to understand how this front actuator works in my 95 tacoma. The front diff is not disengaging. I have no flashing light, the truck shifts into 4x4 fine, but the front end is staying engaged while in 2wd. I have a severe whine I thought was a rear end noise, but now think the transfer case spinning is causing it.
I repaired a cracked hose end on the booster? Side of the actuator. Under the hood there are 2 solenoids, a brown and blue. If I switch the hoses it will disengage but not engage. If I keep them in order it will not disengage but if I pull the blue hose it will disengage.
Once I put it back in 4x4 it becomes stuck again

 

Update.
Still have the whine upon acceleration/load, and I guess it only temporarily became disengaged because I rechecked the front driveshaft and it is engaged. When I have time I will check for a leaking line and then maybe a bad solenoid under the hood?