4x4 transfer case actuator replacement?

I picked up a used ranger. Guy says the transfer case actuator needs to be replaced and 4x4 will work. I order the actuator and climb under the vehicle to remove the old one and install a new one. The old one isn’t there. Someone previously removed it. Tried to slide new one on and it won’t slide on. Am I missing something here?? Why can’t I get this to slide on??

This truck has no power mirrors or locks…. So, what fuses control the 4x4?

Thank you in advance