Good find, icarl. I wonder if this would apply equally to an auto locker.
I've been thinking of putting an Aussie in the front of my Ranger and I've got an in the rear, but thinking of leaving it and replacing later. I'm thinking I'd be better off with a locker/LSD than open/locker.
What do you think?
I'm no expert but I heard that a locker is only necessary for extreme off-roading like rock crawling. I would not put an automatic locker up front as it could cause handling problems. A selectable locker would be best as you can turn it off when you want to turn. Even a limited-slip up front can cause handling issues. The stability of a limited slip in the rear and locker in the front would probably depend on how much the rear slips. If it slips a lot then you may experience similar (but not as bad?) control problems to the locker up front and open diff in the rear scenario.
"In most cases limited slip differentials are fitted on the rear axle
only. This is usually advisable, for when fitted on both front and
rear axles, some limited slip differentials can alter the vehicle’s
handling characteristics and even cause instability at speed.
Modern examples are the Hydratrak which
incorporates a cartridge type fluid coupling which
smoothly increases torque transfer to the wheel
with slower rotation, and the Detroit Truetrac,
which is claimed by the manufacturer to be
suitable for fitting to the front axle
of a 4x4 without causing the handling
problems previously mentioned."
- Taken from 'A 4-Wheel Drive in Southern Africa'
"Automatic diff locks are a disadvantage in soft sand when the
vehicle is turned, as the locking rear axle tends to cause drag on the outside wheel hampering progress. Contrary to what the
manufacturers claim, I do not advise fitting an auto diff lock to a
front axle as it can cause severe handling difficulties on slippery
surfaces. Because they cannot be manually disengaged, when
steering becomes difficult, they are unsuited to front axles."
- Taken from 'A 4-Wheel Drive in Southern Africa'
"Don’t fall into the trap and believe that a four-wheel drive vehicle
must have an axle diff lock before it will be effective off-road. It is
true that there are some obstacles that only vehicles with a lockable
diff will negotiate with ease, but these can in so many cases
be overcome with driving skill. However, if you intend tackling the
very toughest off-road conditions then axle differential locks are
essential. An axle diff lock is a ‘nice to have’ and not a ‘must have’
item.
The ultimate configuration is diff locks on the front and back but
it is essential that the back diff is locked before the front. The best
axle diff locks are the manually operated type and are a desirable
addition to any vehicle expected to traverse very difficult terrain."
- Taken from 'A 4-Wheel Drive in Southern Africa'