In a few words, this forum and forums like this are the BEST.
Now for what might be too many words..but maybe some one will gain some insight from the posting.

Today...The transfer case fluid got replaced, 10k miles since the last changing but since I was doing the transmission, why not refresh it as well, there was some black metallic particles on the magnetic bolt and the color had darkened considerably compared to the stuff that comes from the Bmw fluid. hence, change the transfer fluid to avoid that thing from wearing out prematurely. I didn't worry about any adaptions with both trans case and transmission, it drives fine.

The transmission....it was 20k miles since it was changed, pan dropped, fluid, filter, cleaned. vehicle has 57k miles. First I Drained the pan and filled with engine running, shifting gears, 1-2-3, reverse, drive ect for a few minutes to mix with fluid in torque converter...then drained fluid, dropped pan, replaced filter, cleaned magnets, fluid was very dark, particles on magnets, darkened fluid on solenoids, ect...I use manual almost exclusively and am somewhat aggressive, 4.8is, why not..evolved to putting extra oil in bucket, attaching a tube to a manual pump with a tube and a 90 degree elbow for filling into fill hole, trans has a metal pan, recessed fill plug, elbow makes refill a breeze, but have to pump with engine running, with oil in bucket, it goes in easy, stop once fluid starts to run out...plug and you got it. moral, these transmissions must be serviced with new lifeguard 6, filter and cleaned of particles...otherwise during operation, the contaminants get circulated and inject wear into the gear boxes. I wonder how far off the lifeguard 6 is from the transfer case fluid, it looks about the same coming from the bottle.

Rounded out the event by draining the oil and changing the filter, mobil 10-30...pour the oil in the filter before screwing onto filter housing...the engine will not be starved for oil on startup.
A few months ago, I did the entire gasket change, o ring change to see if I could eliminate the smoke on idle-takeoff... valve covers, solenoids, vanos motors, brake booster, timing covers, left and right..it was dripping oil...these engines run too hot and being aluminum, no wonder they stress the rubber components that are supposed to seal it...paid about $400 for parts, $1300 at the indy who is fantastic but ...she still belches a bit of the blue smokey shit..though not as bad but the oil drip is gone.