[s917]

>Any new Land Rover or Range Rover? They come with 2 locking differentials, with 3rd being an option that can be added extra.

Source? Center locking diffs are more or less standard, rear lockers are options in LR3/4/post 2004 Disco's, Sports and Range Rovers (although standard in some, I think the Supercharged and possibly the SVRs, but I'd need to check) Front lockers are not factory options and I don't ever recall seeing after market lockers for these models advertised.

Defenders, Discos upto 2004, Range Rover classics (and probably P38s) and all series vehicles have the standard after market options for front and rear lockers.

[gambiting]

I had a 2005 Discovery LR3 V8(US Spec, imported to EU) and I could swear it had 3 diffs - at least the 4x4 Info screen would always show 3 diffs working independently when I was driving it offroad. Of course I might be remembering it incorrectly, but a quick search on google shows "genuine Land Rover Discovey 3 front differential" part on ebay, so I guess it must exist?

http://www.ebay.co.uk/itm/like/182246825443?lpid=122&chn=ps&...

[s917]

They have differentials on the front, but they're not "locking" differentials, they're "open" differentials, no locking capability at all.

Center diffs are for the most part (in Land Rovers) locking differentials, though some Discovery IIs had open center diffs and things like Freelanders use a viscous coupling in place of a mechanical diff lock.

Newer models have an electronically controlled locking diff in the gearbox (center) and an optional electronically controlled locking differential at the rear.

But front diffs on modern Land Rovers are open.

Edit: Here is an image showing the locking diffs on an LR3/Discovery 3: http://www.landroversonly.com/forums/attachments/f41/37257d1...

Note the center diff is unlocked (or open) and the rear is locked, there is no option to lock the front, which will always be open.