I have to admit it has to be a really horrible task. Because we are taking the D2 to the UK with a round trip of circa 2000+ miles I decided firstly to grease up my rebuilt driveshafts, 4# UJ's and a shaft slider. What a disgusting dirty greasy job. Next was to check and top up the autobox and the transfer box. The autobox is more complex procedurally starting the engine and exercising the autobox through the gears but the oil looked a bit dark but acceptable. However, the transfer box seemed short on oil so I pumped in about 1 litre of 75-90 oil but once again the oil looked dark and murky. Anyways, in both cases it looks time for some oil changes on both gearboxes when we return.

The only problem I encountered was that having had a knee problem recently and at my tender age I found it difficult jacking it up onto axle stands and messing around under the truck even using a mechanics 'skate (creeper) board' but that's my problem for being too mean and not trusting the local garagistes.

 

You should have drained the transfer-case once you had the fill plug out, (which is the difficult part), since it only takes couple of liters to refill,,
Unfortunately I don't trust local garages either, so I know what you mean,