Jeep sales — juiced by a zero-percent financing deal — jumped 20 percent for the month, making up for lower sales for FCA's Dodge, Chrysler and Fiat brands. Low gas prices, low interest rates, improving employment numbers and enticing new products are also driving consumers to dealerships in bigger numbers than expected. Last week, sales forecasting firm LMC Automotive raised its full-year forecast and said sales are now likely to reach a record 17.5 million in 2015.