quote:
To test it it's on: Jack up the front of the vehicle. Engage the diff lock and put the handbrake on. Try to rotate one of the front wheels ~ they shouldn't rotate. Let the handbrake off and (carefully) try to rotate the wheel again ~ it should try to move the whole vehicle (hence the careful attempt at rotation).
To check it had disengaged: Disengage the diff lock and put the handbrake on. Rotating one of the front wheels should cause the other to rotate in the opposite direction.
Unquote
No no no ....
This will NOT work if BOTH front wheels are off the ground because turning one whel one way with the prop-shaft (and hence the differential in the axle) locked, will merely turn the other wheel on the same axle the other way.
THE way to tell if a 4wheel drive like a Landy has the centre diff locked is to get the front end (or back end - it doesn't matter) raised on a trolley jack which is pointing where the car is pointing, with both wheels clear of the ground.
FIRST, with the centre diff NOT locked, very gently try to drive forward a foot in first gear. If the centre diff is free, the front wheels will simply spin and the car will not move. DO NOT TRY THIS WITH MORE THAN TICKOVER REVS!
SECOND, with the gears in neutral, lock the centre diff. Again, at tickover speed only, clutch down, engage first gear, and even with the front wheels right off the ground (trolley jack, remember?) the car will try to move forward when you ease the clutch up gently.
This must be done with great care or damage / injury can result, but it PROVES if the centre diff is locking up.
If the centre diff is free, i.e NOT locked, if any ONE wheel slips you lose all drive to all 4 wheels. Locking the centre diff means if any one wheel slips, you lose drive only to the axle the slipping wheel is on - the other axle won't lose drive because of that.
CharlesY
CharlesY