Hey All, If you were following the saga my 88 535isa with a slush box started downshifting all by itself from 4th to 3rd over a 4 om. period. it finally started doing it every 5 seconds last week. After calling 900 different people who gave 900 different answers, it turned out to be the selector switch at a cost of a six pack, courtesy of Bimmerworld.com. One piece of advice is NEVER ask a transmission shop for answers, I called about 10 and they all said it was the clutch pack in the tranny( $1250-1600) or some other BS that required a rebuild. Thanks to all who replied