2004 X5 3.0d with ZF 6HP26X (6 speed) with 155K KM on the clock. I have been doing a lot of reading and researching on whether to change the oil or not. It is so confusing! In the end, I took the plunged! BTW, the auto trans is working perfectly before the oil change. My requirement is that the filter kit (filter (Filtran) and the pan gasket must be original - I was not able to buy the kit set here) and I took it to an Auto Trans specialist for the work to be done. There is nothing special about this ZF transmission as it is being used quite extensively by other car manufacturers.
I was allowed to watch every step of the oil change process which was great.
The drained oil was relatively clean (a bit darker than fresh engine oil but thinner) and have no burnt smell (a good sign as smell of "rotten egg" would be a bad sign!). The pan is also relatively clean with a bit of mud-like stuff on the two magnets.
Whether to use the BMW specified oil or not has been a major bone of contention. It all boils down to cost and the myths (as in "lifetime" and "sealed" and "maintenence free") that goes with it. The BMW specified oil is about three times the "equivalent" best oil in the market for me here. It is also hard to get the BMW specified oil or the ZF lifeguard5/6 fluid.
After much persuasion and more reading, I went along with filling the oil with Penrite Dexron-VI ATF (red in colour). I probably will do another oil change in six months time although I have been told that it is a waste of money. It should be good for another 30-50K KM. I am servicing the transmission as part of preventive maintenence and peace of mind. I intend to keep the X5 for a while.
Excerpt from Penrite Technical Bulletin: May 2006
"ATF DX-VI - just release to market for 6 speed GM automatices, is also recommended for ZF 6 speed automatic transmissions (6HP series) which are found in BMW, Range Rover, Jaguar, MB, VW as well as in the new Ford Falcon BF and Territory SY." More info here,
http://www.penriteoil.com.au/tech_pd...S%20UPDATE.pdf
Whether this refers to drain, filter change and refill, full flush or rebuild, it did not clarify.
So far so good. I will keep you guys posted if something untowards happen.
Happy driving.