Jammed Diff Lock - What do I check?

I've just got an '89 RR V8 Vogue automatic running again, after being out of use for the last three or four years.

As far as I can make out, it is jammed in 'Diff Lock', and judging by all the tyres being bald, it had probably been jammed before it was taken out of use due to a brake problem (a steel cable tore off one of the front brake pipes).

The vehicle is used on an airfield, so 2mm of tread, whilst good for traction wasn't required by the Plod.

Having just put decent tyres on the vehicle, I would like to get the diff lock unjammed before these tyres also get ruined.

Can you please suggest a course of fault diagnosis and rectification that I could try, to unseize the diff lock?

Thanks,

Robin

start with changeing auto oil and lube all linkages up and see what happens...

does high low lever move to side for diff lock? I had 89 classic, it had the borg warner transfer box which has viscous coupling so no centre diff as such so no diff lock. try driving round in figure 8 see what happens but if its seized think only cure is new coupling.

Thanks Guys,

Come to think of it, this one does have a Classic badge on the back, so its probably the same as yours (we have three Range Rovers and at least one is a Vogue).

I can't make the high/low lever go from side to side, but I do get a lot of tyre noise when turning, so the viscous coupling siezure sounds very likely.

As the vehicle only drives about 2 miles a day, Saturday & Sunday, away from public roads; are there any 'bodges', for want of a better word, to breathe some life into the viscous coupling even for a short while? I'm thinking along the lines of drilling a hole in it and putting some more of the fluid (whatever it is) in. The couplings are £199 on eb*y, and the whole vehicle is barely worth that, and likely to be disposed of in the next few months, anyway.

pretty sure it will have the borg warner transfer box on that year, driving round in figure 8 gives coupling a work out and can help free it up if only partly seized but replacment is only real cure I,m afraid, sorry but sounds like you will have to live with it if going to scrap it anyway,hope this has been of help to you.

Thanks KDS. I have seen references to the figure of eight thing but I didn't realise that was to exercise the coupling. I'll definitely give it a try after putting the knackered tyres back on first!

One initial thought I had, was to get at the coupling and direct a hot air gun on it, on the basis that if there is a liquid in it, warming it might get it to move around and lubricate any dried out places. Having just read what Wikipedia has to say about viscous couplings though, this might have exactly the opposite effect, as the liquid in it goes solid when it gets warm. A freezer spray is more likely to do some good!

The pictures on Wikipedia are good, and I now have a good idea of what should go on inside the coupling.

if you are scraping the car in couple months a simple quick fix would be to remove the front prop shaft, half hour 8 nuts and bolts job sort of sorted, dont think you can remove the bolts from gearbox end drive flange so put washers on as spacers and put nuts back on.