• What is the TQ or HP rating of the gear set?
Please refer to JB conversions website for more information.
    • How is crawl ratio calculated?
    Crawl ratio is calculated by multiplying your transmissions first gear ratio by your doubler ratio (if equipped) then your transfer case ratio and finally your axle ratio.
      • What input shaft spline count do I need?
      Please refer to Tech page for more information.
      • How much length does the 4 speed option add?
      The 4 speed option adds 5.33" to the total length.
      • Can you do front digs with the Rock Box?
      Yes, the Rock Box is capable of doing front digs in high and low range.
      • What shifter assembly do you guys recommend?
      We highly recommend JB custom fabrication for shifters, made in the USA and specializing in stainless steel twin-stick shifters.
      • How much does the Rock Box weigh?
      Total weight when configured with 4:1 gears and 32 spline shafts is 72.6 lbs.
      Yes, Every part will install into the case with the exception of the front output cover and shifting assembly.