Not reading the other posts, I'll go straight to the point, open the rubbish bin, drop the stock jack in and close lid, forget about it.
Go to any spare parts place, Supercheap should do fine, buy a 1,200 - 1,500 Kg trolley jack.
Problems solved, the stock POS is not worth the trouble, they have been known to remove fingers, quite often.
If on a budget go to the wreckers and grab a Landcruiser jack, they should be easy able to lift an entire end up NP.
On the diff ? sure, the stock thing has to lift the suspension before a wheel will leave the ground, on soft ground they are dangerous, "always" keep a 12" square piece wood, enough so it fits in the spare wheel, 3/4" thick form ply does OK or similar to use under whatever jack you use, takes bugger all space and will save your fingers and feet when the stock jack collapses or rolls over.
It's Very handy to make up some chassis stands, cost stuff all and is a good rainy day project, and real handy when working under a car, why the V8's don't allow mechanics under a car unless the air jacks are blocked, similar deal.