The ideal upgrade for performance vehicles with the GM 6L80 transmission, Sonnax extreme duty 4-5-6 clutch hub and intermediate shaft 104680-45 guarantees maximum protection against shaft breakage. The unique hub design improves oil flow and accepts Powerglide-style frictions to optimize clutch durability. In place of the two-piece shaft/hub, Sonnax uses a much stronger, one-piece design that eliminates the OE assembly's weak, welded connection. The one-piece design is custom forged from ultra high-strength 300M billet steel, then heat treated and shot peened for added durability. This combination of features guards against broken 4-5-6 hubs and the risk of rear splines shearing off — chronic failures in performance cars and trucks as well as heavy commercial vehicles. The 4-5-6 clutch is released in 1st, 2nd and 3rd Gears, and at high RPMs, constant oil flow is required across the clutch frictions to prevent heat build-up and damaged clutches. The unique upgraded design of the Sonnax hub doubles oil flow to the clutches for significantly more protection against heat build-up and clutch failure, especially compared to other aftermarket shafts that reduce oil flow. Since Powerglide-style, 45-tooth frictions are a popular 6L80 upgrade due to their wider friction surface, this extreme duty shaft features that style of smaller-diameter hub and must be used with Sonnax high capacity piston kit 104960-20K. For best performance, use with Sonnax steels 104120-01 or 104120-02 and Borg high-energy frictions 104120-03.