The heavy resistance has been solved as hand brake cable nuts not being done up. As the gearbox moved on its mounts it would snatch on the hand brake causing it to engage.

I know it's stuck in diff lock because every time I drive it just up the drive and back and then jack up a wheel the wheel spins a little to unwind and also no wheel will spin past half a rotation in any direction.

It would appear though that it has been left in diff lock for the 6 years it spent dormant. The six years may have caused something to seize as the four wheel drive worked prior to the six year rest it had.

Okay another update.
I took the plate off on top of the front output housing where the linkage attaches to and is held in with 3 bolts.
The mechanism all moves nicely by hand internally and I moved it both directions as far as it could go and could see it moving yet still it's stuck in diff lock. I cannot get any wheel to move past half a rotation. I tried tapping the casing with a wooden mallet to see if it would free anything and it didn't. Still have the front and rear axles locked together.

I might try unscrewing the diff lock light switch to see if that's interfering with anything.

The mechanism is all moving nice and freely. Just won't budge out of diff lock.

with it out of difflock - ie the operating lever fully anticlockwise, try reversing 50 yds or so - it is common to have to do this to release difflock. wind the switch out so that that isnt stopping it as well. Is the difflock light on, or not?

Hi tried doing all what you said and still no use. I know the wind up can last a while as on my defender 90 sometimes it can.
I've removed the switch completely as there was no wiring to it so no light.
I'm going to search for some exploded diagrams of the diff to see what may be seized but still allows the selector fork to move.

109inches said:

Hi tried doing all what you said and still no use. I know the wind up can last a while as on my defender 90 sometimes it can.
I've removed the switch completely as there was no wiring to it so no light.
I'm going to search for some exploded diagrams of the diff to see what may be seized but still allows the selector fork to move.

Click to expand...

the selector for diff lock is not directly operated by the spigot ,moving the spigot tensions a spring which pushes on selector only if selector is free to move will it move , this is so diff lock can be operated on the move once youve tensioned spring for either in or out it does it when shafts align or strain is removed

Sit rep- still in diff lock.

So I'm assuming this isn't a common problem where all the mechanism works until you get to the spring that operates a selector which is where the problem is.

I drained oil out the transfer box when I bought it and replaced with ep90 so a component that sits in oil surely cannot have seized?

I've tried tapping the area of the case where the spring lives to see if that frees it off but no.

Still haven't been able to take it off road as I've been told I can't make the fields a mud bath after all this heavy rain so got to wait until it dries.
However I do have brakes now and it will stop.
Paddock are also delivering the last order I need to get it road worthy assuming the transfer box isn't going to need removal.

So the issue has been discovered and it's not good news.

The centre diff has welded itself together after being used in slippery conditions with the diff unlocked. According to Ashcroft transmissions this can happen in 10 seconds. That explains why it was parked up and why it had the linkage removed.

It's all a game.