I replaced the standard plastic axle housings with Vanquish Products’ Currie F9 axle housings and hardware. I really like the look of these axles! The center axle had to remain plastic so that I could create the pass-through required for a 6X6 center axle. All that’s required for that is two output halves of the standard plastic axle housing and a second output pinion. Another benefit of the Currie-axle upgrade is that the final drive axle can be flipped—necessary so that they all spin the same direction!