Front HS bulkheads enable diff height adjustment using eccentric bushings. Inside front side part gearbox, the diff height has a 2mm modification range which 2 Dot is for middle diff place. The diff height modification is an essential set-up ability which allows fast set-up adaption for either Carpet or Dirt songs. Carpet variation operates with lower trip height as well as keep carefully the drive shafts directly the differential is devote top spot. Dirt variation runs with top trip height as well as keep carefully the drive shafts straight the differential is devote reduced place. Fits XB4'21
