Good fuckin question Harleymark.
i have done 70,000km on my '07 lowrider [ 32,000km on it when i bought it].engine oil every 4-5000km and primary/trans oil every 8-10,000 km depending on how long the last/next trip is.HD mineral in the engine,JD hygard trans oil in the primary [ clutch is much nicer with this oil ,former JD field tech ] and HD formula in the trans.cold in gear is good,neutral is never a problem hot or cold.as others have said,oil and filter changes regularly help everything,at the end of the day oil/maintenace is cheap.
Hey speedzter this particular oil has these specs, API SN/CF, JASO MA2 so it is ok with my clutch, the 10 at cold start up is clutch friendly, the 60 at temp is compensator friendly, I used to use a straight 50, I find this slightly better when selecting first cold, HD have an 80w140 gear oil they put in the primary, CST wise I like the penrite better, do you notice any comp wear with the 30?
So the JD hygard is John Deer stuff? I use Belray primary chaincase lubricant(for the primary)- https://www.belray.com/product/primary-chaincase-lubricant/ it was recommended by Fuelmoto USA who do plenty of performance builds and done 100's of trips down the drag strip, it is a mineral based product, Redline shock proof for the trans, Penrite 20w-50 for the engine