My ZF has just started to make a "squawk" sound on the 3-4 change. After a bit of research I've found this to be very common in the Euro cars with these transmissions. I'm getting a service and inspection done of Friday which will hopefully fix or at least identify the problem. I'll be using the Lifeguard 6 genuine oil. I know others have tried different brands, but the genuine oil seems to be about the only one that doesn't have a bad story about it somewhere. My advice would be to not buy that "sealed for life" rubbish as ZF themselves have put a life span on the oil. The general consensus amoung the Euro seen is to change it every 60,000km's. I'll be doing that from now on. Oh, in case anyone is wondering "squawk" is the official technical term too.