RA Rodeo - Where are the 4WD actuators?

Hi All,

I notice that if I haven't selected 4WD for quite a while it takes several tries of switching between 2wd and 4wd before it successfully selects 4wd.
I'm guessing that there is some sort of actuator that is possibly gummed up through lack of use and needs a clean/lubrication?
Does anyone know where this is located so I can have a look at it?

Thanks in advance,

Greg..