Redesigned super-strong FRONT bulkheads are narrower to go the arms more into centerline to come up with more traction and to provide a better range of track width adjustment. The bulkheads have actually an ideal fit on updated differential and are reinforced to improve the reliability. The XB4 bulkheads allow super-fast & easy diff exchange and servicing by dismounting just 4 screws through the front associated with bulkhead and bottom associated with framework. This super-fast diff access is available at both front & backside. The bulkheads have minimized ball-bearing play, leading to increased gear teeth lifespan and minimized gear stripping.