Well as hoped I managed to get a couple of hours to tinker with the jeep today. I figured that if I was going to check the state of the diff oil, I was going to have to replace it so I bought three litres of the correct Comma stuff to do so.
Before I drained the diff housing I decided to evaluate the LSD operation properly. I chocked the front wheels, released the handbrake, selected neutral, then raised one rear wheel at a time ensuring the other was firmly planted and physically tried to rotate the elevated wheel. This time there was resistance but not enough that I couldn't force the wheel around with a bit of effort. I then placed wooden blocks under the axle to support each side in turn and engaged first gear. All that happened was whichever wheel was in the air simply spun around. I changed the oil and carried out the same tests again certain the results would be the same which they were. The old oil was not as dirty as I expected; in fact it was a transparent grey colour and there was some sort of gooey sludge stuck to the lower bung but the oil itself definitely didn't look like something that had been in there forever and a day.
It looks like the LSD is indeed goosed. Now, I am one of those people who isn't too keen on non working items, basically if it is there I like to have it in working order but I hear what some of you are saying i.e. that it may not be strictly necessary to have a LSD. I have just watched a video on Youtube where a Terrano is climbing over some rocky terrain and while one rear wheel is definitely not moving, the other is spinning, much like mine would no doubt do in the same situation.
As I said earlier, I really am a novice when it comes to jeeps having never owned one before but given that during the worst of the weather here last Spring, the only vehicles mobile in this locality other than some 4wd tractors (mine got truly stuck while helping free stranded vehicles on the road) were a 3.1 Trooper and a 4.2 Land Cruiser (which unbelievably pulled out the tractor and beforehand a 7.5t recovery lorry in reverse), vehicles I know to have difflocks which were most definitely used that day. It is heavy snow, hilly sometimes muddy fields, pulling heavy trailers etc that make me think the LSD might be a desirable thing to have should conditions be poor. Am I way off base in thinking that?
Thanks,
Michael