Quote from Giggsy. [Well the hubs are on my list of stuff to do, just another q though, how do the man hubs turn on (off?) when would you need to turn them into the off road way and what is the down side to leaving them off road mode?/quote]
If you go under the vehicle (In standard 2 wheel drive) if you rotate the front prop shaft( coming out of the front of the transfer box) by hand the front hubs should engage within a revolution or two of the shaft. (found this out once when I rotated the front shaft to grease it ).
If you can keep rotating, then one front drive shaft is probably still turning and that is the hub which is not engaging. Get someone to look with a torch at the front shafts, of put a blob of paint on each drive shaft and keep checking.
How they work.
When you select 4x4 the front prop shaft starts to turn and this engages both hubs.
To de-select, go to 2 wheel drive and reverse backward about 2 metres and the reverse rotation of the wheels disengages the front hubs.
Sometimes this doesn't always work ( you may hear a clicking noise) and you may have to select 4x4 again and try it again etc.
Leaving the hubs engaged while in 2 wheel drive mode just drives the front diff assembly, this uses more fuel and makes the steering a bit heavier. Quite useful in bad weather to leave them engaged and slip in and out of 4x4 as traction is lost in the snow. (saves reversing back).
Warning having 4x4 engaged on dry or grippy roads will cause "wind-up" in the transmission as the tyres will be slightly different sizes and this can cause damage to the transmission and excess wear to the tyres.
In fact if you engage 4x4 on dry tarmac, the vehicle will appear to come to a halt in a few feet as the tyres fight each other. This has been mentioned by a few members when they first get a vehicle and want to play with the 4x4 mode. IT MUST BE AVOIDED.
Hope this helps to locate the faulty hub.
Best regards, Rustic