The clutch plates are different thickness, so they have to be set up with the right pressure plate, to give them the right clearance, when they are assembled. Part No. 3 in the parts diag is the pressure plate in a number of thickness to set the clearance. My WSM has a different clutch, so you would need to check the US book to see what the clearance should be.
Although the C solenoid is clicking OK, you should check or replace the Transfer valve to make sure that it is not jammed. You will have to knock the roll pin out to get the valve out, of the valve assemble.
Harvey.
