I'd check your diff oils asap too.
You need to drive it to get the oils warm not just the engine.
That oil looks awful. I would be tempted to refill and run it good and hot and redrain/refill again to flush it clean(er).
Edit- lynall beat me to it.
If you want to extend the pipework it's 6mm OD nylon, available from eBay or your local pneumatic place.
Defender axle breathers use the same size tube as well.
Breathers, don't blank them.
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