If you study the pictures on the blog that I linked to, you will get a clearer understanding as to what drives the white nylon Water/Oil pump gear; that being the primary gear on the end of the crankshaft.
The gearbox oil pump appears to pump oil to the layshaft (countershaft) as you say, sucking the oil from the bottom of the gearbox through a wire mesh filter, via a pretty tricky path through the cases.
I am just too lazy to pull apart my old/parts engine to suss this out properly I guess. But still am quite curious all the same.
Surely someone on this site can easily answer this?
