The 1998 BMW 5 Series has 2 recalls, the more serious affecting 528i models where a faulty transmission gear position switch seal can allow the car to start while in Drive or Reverse.
Water can work its way into the transmission gear position switch over time, causing it to misread which gear is selected. The result is that the vehicle may not start at all, or it may start and lurch forward or backward unexpectedly. The second recall affects 540i models and involves a differential pinion shaft that wears prematurely, first producing noise from the rear axle and eventually causing a complete loss of drive power to the rear wheels.