60 series cruiser swivel hubs & starter

G'day,
I have two quick questions re maint on a 2h Diesel 60 series cruiser, (I love my truck....it takes me where I want to go....) when checking grease oil etc do the front swivel hubs get lubricated via the diff oil or should grese also be put in through the filler holes on top of each swivel housing?? Also it has had a niggling starting problem that no amount of new batteries trips to auto elictricians seems to be able to get a handle on. Occasionally (especcially when the motor is warm), the starter motor will struggle to turn the engine over, (I have had to roll start this thing from so many petrol stations it's not funny...) The charging system has been checked, the stater has been checked and all contacts re done, new batteries purchased, but it still feels "weak" occasionally and I am about to head bush, (googs track, Uluru, Tanami track, Kimberlies, Broome and all that good gear) and do not like the idea of having to continually roll start. I was given advice by a mechanic that the only way he knew to prevent this, (he had three 60 series with the same prob) was to run a heavy duty earth wire from the starter directly to the battery. Is this an option?? and has any one had these drama before

thanks for your help