So was under the car doing oil change and spy a drip of red on the gearbox level/drain plug. Touch it and the level plug moved freely. I thought the undertray looked oilier than usual.

Open up the filler plug and I make sure i've got all I need in the magic box of LR parts before taking out the level plug.... Engine running - nothing comes out (as it should be) and about 200ml comes out with the engine off (that should be 500ml). Turns out the o ring had come apart. Was a new LR o ring from when done last. Means my gearbox has been slowly leaking when engine off and i've lost about 300ml over god knows how long.

So yeah, good excuse to do a couple of drain/fills on the gearbox oil. New o ring. tightened up properly. Feeling lucky saw that before it got any worse. Drive this morning the gear changes notably smoother - no idea if it was the level or the fresh fluid, but still, was a good feeling.

And always make sure you can undo the filler plug before draining any lubricant - they can be very tight. Jules

Must have been your voice i heard in my head just as i was about to undo the level plug!

there are threads on here about impossible to remove gearbox filler plugs and how to get them undone.

It happened to me once on my old Defender; the LT77 gearbox filler plug square end just rounded off with the spanner and of course Id already drained the oil  Jules

jules wrote:

And always make sure you can undo the filler plug before draining any lubricant - they can be very tight.