In its simplest form, low range is always perminant locked 4WD, so put it in low box. Crall underneath and try rocking the propshaft, it should be locked so it turns with the rear propshaft. If it does, this is good! When the box is put into high range and the yellow button is aloud to pop up (if it was depressed for some resion it should pop up as you entered low range) the propshaft should now not be locked to the rear axle. If for some resion this isn't happening you have a fault with the transfer box.
Next up is the front axle, jack up both wheels and surport on axle stands. When playing with the FWH you should be able to feal one setting is definately free and the other is definately turning the halfshaft aswell. Turn both hubs to this position (4x4 or locked). You should now find spinning one wheel will make the other turn backwards or the prop turn. If you stop one wheel turning at all by putting it on the ground, the turnable wheel should turn the propshaft. If it doesn't then eather a hub or an halfshaft is broken. Try eather side. Last test is repeat this with the transferbox in 4wd (low range or yellow button) - you shouldn't be able to turn the 1 wheel off the ground now. If you can the splines on the propshaft have probubly gone alowing one end to turn and the other spin free.
Some people find the transmition a bit confusing but they aren't really that bad once you work out exactly what each bit does...
Transfer box works as follows, High range = RWD, press yellow for 4wd
Transer neutral and low range are both always perminant 4wd (like having a centre difflock engeaged). To cansel high range 4WD you need to go into low range and the button will pop up.
FWHubs are extra to this, they just disconect the halfshafts from the hubs - you'll want both locked to be able to get 4wd. Only unlock both together when your useing RWD high range. Leaving them locked all the time or removing them all together does no harm, infact I'd recomend binning them if you use 4wd most the time, they are simply more to break.
If you notice the landy apears to be Front wheel drive only and wont drive atall in high range without the yellow button you've bust a rear halfshaft.
