My '92 has stopped 4wding. 3.0 Petrol Auto. Move 4wd lever and the dash light flashes briefly and a couple of clicks but nothing happens.
Where to start looking?
Thanks

 

I assume you have ADD (automatic disconnecting differential, not Attention problems). There are two vacuum lines to the differential; one to engage, one to disengage. Check for damage, leaking, the usual. You can pull them off and use your thumb to check for vacuum as someone switches the actuator (lever).