Hi guys, New to the forum 
Need your help 
I'm from Saudi Arabia and here sometime people sell their car just because they couldn't get parts for the cars .
I have Chevy k30 1983 
and problem is that when i use the 4WD Hi or Lo the 4WD seems to disengage and engage in less than a second and it every 10s or less if I'm climbing 
I asked a mechanic and he told me what's wrong but I couldn't find the parts I was locking for and I couldn't search for it in the internet because I don't now the name of the parts in English . 
so I need your help guys a link would be great 



As I searched I think what I'm locking for is something like this ? 

sorry for my English - -"