Rockwell cases the power gets transfered to the idler shaft and then to the output shaft in 2H. The gear whine will be louder when the idler shaft gets wear between the gear and shaft (this causes misallignment therefore louder whine), not too much you can do with it. I fixed mine up good, but it did requier modification and a whole new idler shaft. As far as transmission whine there really shouldn't be any in high gear. Power is transmitted straight thru, the counter shaft is still spinning though, but with no load there should be no whine. As far as lube my '67 GM service manuel says "Either SAE 80 or SAE 80-90 multi-purpose gear lubricant". Ditto that for the transfer case.
