4x4 Problems

I have a problem my truck had the actuator replaced with the new style one and i have 304,000 miles and i think it went out and all i can afford right now is the old style but when i took out the black one and put the new one (older style) in it seemed as it pressed against a spring like thing and i had to push to start the threads and it went all the way in problem solved or not but as i drove it seemed even in two wheel drive my front axle was still engaged. So i want to know if this was a direct problem of me putting that actuator in by pushing against the spring like thing. Any help would be nice thank you.

When the new style actuator was installed, a spacer was inserted into the front axle to make the newer style work, you'll have to take the actuator out and remove the spacer for the old style actuator to work correctly