Marlin Crawler Billet Shift Fork for R154. This is a CNC machined 7075-T6 billet shift fok for the 1st to 2nd gear shift inside the transmission. The stock part is made of a softer metal and it can wear irregularly, or even break with hard shifts and heavy use. This is one of the sweet new items from Marlin Crawler, designed to give you the strongest and most reliable R154 possible.