The 5-speed Sportster transmission has seen many changes over the years. Most gears for 1991 thru 1993 models can also be used in 1994 thru 2005 models when installed with the same speed gear on the opposite shaft. Andrews gears and shafts are made from high nickel alloy, heat treated and shot-peened to give maximum durability and strength. Also, where applicable, lead-in ramps have been machined into most gears to improve shifting and reduce wear on drive dogs and drive slots.