Originally Posted by
Bush65
AFAIK, 99 was the change over year and disco I's were still available in early 99.
For sailors_mission, tail lights on disco II are higher (up around window level). Disco I tail lights are lower (below window level).
If disco I, the knob on the high/low lever has a diagram on top to show the hi/lo and lock/unlock positions. But sometimes the knob gets twisted around to the opposite orientation and could miss-lead.
The lever should be across to right to unlock and to left to lock (forward for low, rearward for high).
The indicator lamp is meant to represent 4 wheel drive - it has lines to represent the 4 tyres and lines to represent the axles between tyres and driveshafts between axles - like a 'H' character.
If the lamp is on, it is still possible that the centre diff is not locked, but that is not the case here.
The centre diff is locked by the action of a spring, not directly by the lever and linkage (the linkage merely pushes on the spring to increase the spring pressure).
If the indicator switch is sticking or adjusted down too far, the spring can not lock the diff.
If it hasn't been used much, the linkage can stiffen up and not lock.
Mud and gunk can build up around the linkage and prevent the diff locking.
If the plastic pivot bushes are worn, the linkage can loose motion and not push the spring far enough.
If the pivot bolt is not adjusted properly ....
First check around the linkage to ensure the area is clean - right side of gearbox and above front drive extension housing of transfer case. Check from underneath vehicle, no need to pull anything off, but may need a light/torch.
Spray the linkages liberally with WD40 or similar.
Engine off, chock wheels, jack under front axle and lift front right tyre just clear of ground. You should be able to rotate the tyre that is off the ground with centre diff unlocked, but not when the centre diff is locked.
While the tyre is still jacked up, shift the lever to the diff lock position. Then listen underneath, close to front of transfer case while you rotate the front right tyre. You should be able to hear the diff lock click in as it is locks and the tyre will stop rotating. Shift lever to unlocked, rock the tyre forward/back and you should hear the diff unlock.
If you hear/feel (through the elevated tyre) the diff lock/unlockclick and the light doesn't come on or go off, there is a problem with the switch, lamp or wiring.
You said:
If you buried the front, then the centre diff was most likely locked. Usually when you fail to proceed, if the diff is unlocked, the front tyres do not turn and one rear spins.
BTW, always lock the centre diff offroad when the surface is loose, rutted or rocky. You need to avoid prolonged spinning of any tyre while ever the centre diff is unlocked - this leads to wear and rapid failure of the centre diff. It won't harm the centre diff if the tyres spin when it is locked.