'95 International Module Truck

I am a young mechanic that has never had to deal with the power divider lock on a truck before. I have a customer, with a '95 international, that the power divider was staying engaged all the time. I took the assembly on the front drive axle apart and found that the piston was froze up, so i ordered new parts and installed everything the way i found it. I later figured out the the way it was put together in the first place was wrong and that it was missing a spacer between the bottom half of the housing and the face plate where the air valve threads into. My question to y'all is how this system is supposed to work? I would like to know that way when i receive the new kit and install it I will be familiar with how the system works and I will have a better idea on what to look for. Thank you all for taking time to read this and hope someone has some answers for me.

 

Do you happen to know how the power divider is supposed to be plumbed, or have a diagram that shows this information?

 

Model number of the differential is DT402P. I am not sure of the model number of the lock assembly, my information is at the shop.

 

Ok well thank you for all your help so far. The truck is a '95 model module truck.

 

I don't know. How do I tell?