Dub8, my 4600 has a slightly different set up, instead of having the reverse on the main (1,2,3,4) gear handle, I've got the "fancier" model with a fwd rev shuttle handle which was designed with the attachment of a front loader in mind, apparently they were quite popular with small dairy farmers as the mainstay tractor and able to muck out and act as a forklift.
I think in addition to the main gears mine has a lock on the F/w shuttle.
As far as oil, I don't have a manual I just use the same engine oil as I use in the land rover and put hydraulic oil in the power steering.