Grannville wrote:

As unlikely as it seems, my gearbox oil seems to be overfilling my transfer case and its leaking out. I assume there is a seal on the output shaft of the Gbox and a seal on the input of the Tcase. Seems unlikely fluid wouldn't just come out of the joint between the 2. Am I missing something here? Any and all advice welcome

As above really. Check your breathers for 10.

There is indeed an output seal on the R380 and a separate input seal on the LT230. But critically there is a drainage route between the two gearboxes to prevent the possibility of cross breadbox contamination.

So... Breathers first.

But. It is possible that some hack went crazy with the silicone between the two gearboxes and completely blocked up the drainage channel. It happens a lot. Customer goes in. Oh my gear box is leaking. Garage goes oh ok we will take it out and have a look. Cleans it up and glues it all back in place. No more leak. Except it is usually the intermediate shaft that is leaking and it doesn't drain into the drainage channel so the leaks re-occur in time.

You will find your breathers down the back of the engine up against the bulkhead. Let us know how you get on.