Looks in reasonable condition for $40. I had one some where but haven't seen it now for a few years ,from memory I had 10 self propelled Victa mowers but have just scrapped a couple of Power Plus self drive mowers and a lot more VC mowers are going, at least that will be another 60 mowers out of here.
The grease spec for the gearbox is on this link https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/63421/Re:_Victa_self_propelled_gearb.html
General purpose automotive NLGI#2 lithium 'chassis grease' will be fine. Use a moly [MoS2] enhanced grade if you like, but it's probably not necessary.