An essential upgrade for any hard-working GM 6L90 transmission, Sonnax heavy duty 4-5-6 clutch hub and intermediate shaft 104690-36 guarantees maximum protection against shaft breakage and clutch failure in any vehicle pushing stock components to the limit.

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 1^st, 2^nd and 3^rd 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.

6L90 transmissions also have a tendency to chirp/squawk on the 3-4 shift when the 4-5-6 clutch applies. Unlike aftermarket, two-piece shafts that increase the risk of noise by eliminating the OE dampener, the heavy-duty Sonnax hub/shaft can be used with the dampener.

• Rugged, one-piece design eliminates the weak connection where two-piece hub/shaft assemblies fail
• High-strength, 300M steel forging is heat-treated and shot-peened for maximum durability
• Doubles oil flow to the clutch pack for greatly improved resistance to heat and longer clutch life
• Designed for use with OE dampeners to minimize risk of chirp/squawk
• Use with stock clutches