An update today: No, neither the diff or output shafts are turning.
I have changed the new slave cylinder for another new one today. The clutch pedal now feels good as it should do.
However, the following things are now happening:
1. As soon as engine starts there's a rattle of what sounds like loose gear teeth trying to mesh. The sound goes when I push the clutch in.
2. Difficult to select gears in both boxes with engine running (ok with engine off). Tends to jump out of hi-range on the transfer box.
3. Engine will stall abruptly if transfer box in hi/low range and g/box in gear. It'slike something has locked. The whole vehicle comes to a shuddering stop.
4. The vehicle is on axle stands with no wheels on. Handbrake is off and works ok, nothing jammed there.
5. To add to all that, the engine initially sounded good; nice idle, I could hear air being sucked in through the airbox hose which is connected to the turbo (no airbox on yet). All sounded good but now as soon as I start it, it chugs away really loudly from that same pipe, almost a popping noise with very noticeable suction and it doesn't want to rev easily like it did
What the hell is happening as I'm lost for ideas