Do yourself a favour and change the transfer case oil while you're in there.
My wife's X3 chewed up a transfer case just after motorplan ran out, around 120000km I think. The drive chain was stretched out and made horrible grinding noises. We ended up replacing the transfer case for the sake of having peace of mind.
The yellow lights came on again around 250000km with the clicking noise. I bought a replacement actuator gear drive from ebay for $20 or so, and fixed the actuator, problems gone. I changed the oil at the time, it only takes 1 liter but costs like R700-800 from the dealers.