System reset yesterday just help smoothing the ideling, but it did not fix my "no reverse" issue.
This morning, crawling to my indy garrage (about 3.5 miles) on a less than 20 MpH speed (& put the gear in neutral position at every traffic light...I don't know if it helps or hurts?).
Moment of the truth...
After dropped the pan, not much "lifetime" fluid ~2 Qt. or less (...is this a normal vol. we expect?) came out from the drain plug. The "lifetime" fuild is quite thick, no burning smell. The color is dark red, but clear. The filter is warping a bit out of shape. There is a few metal dusts on the magnets. The best is...no piece of metal in the pan.
Here are my options:
a. Replace only the valve body (+ filter, O-ring & gasket + tranny fluid/diff)...$550 & no warranty if it will fix the no reverse issue.
b. Rebuilt the tranny (+ filter/O-ring/gasket + tranny fluid/diff) & replace the rear main/crank seal (since the tranny has to be detached)...$2100 & w/ 12 months (or 12K miles) "no out of pocket" warranty.
Yeah, I decided to get the last one for the peace of mind....$2100 !!!
Hopefully, it will prolong the life my 540i for another 2-3 yrs.
:^(