if you used a HTB grease the motor
would most likely wear out before the gearbox.
Point taken Max, yes when cold the spool or blade doesn't like to spin freely but soon warms up and spins easily.
Now I'm confused re: the various replacement gearboxes, I had a good look around on the various ones available online/ebay, etc.
They all show a splined female inside the gearbox but my driveshaft is not splined but is a rod with two flats.
My machine is only about a year old, maybe Honda has made changes. I will ask about this when next at the dealer, although I should imagine he may not be very interested if told about generic replacement gearboxes :-)