Stop worrying about input shaft failure when running the GM Powerglide in even the most extreme applications. Sonnax offers the only big input shaft upgrade with custom components designed to work together for reliable performance. The system was a big success when introduced in 2017 for Sonnax 1.58 and 1.65 ratio planetaries, and the company recently expanded coverage to include 1.69 and 1.80 ratio builds. Whether you have an existing assembly or start from scratch in the gear ratio of your choice, it’s the best way to connect huge power to your transmission for great run after run with minimum downtime.
The only way to prevent twist and breakage from massive torque is to increase the input shaft diameter, and the core of the big shaft system is big input shaft kit 353532-01K. The shaft strikes the perfect balance between strength and ease of installation with a 1-1/8″ dia. and a unique, high-strength spline that still fits through the front sun gear. It delivers 35% more strength than the best 1″ shafts, a dramatic upgrade for racers that want to take full advantage of the lightweight and efficient Powerglide transmission.
Mating up to the shaft are Sonnax’s big shaft stator tube kit and rear sun gear kit, every component refined for maximum durability. These big shaft parts work flawlessly with Sonnax Extreme planetary assemblies and Extreme strength output shafts to deliver unrivaled performance. A simple change to a 35-spline turbine hub is all that’s required to level up with this unique system.
Selecting the right components for a big shaft system is easy. Decide what gear ratio you want to run — 1.58, 1.65, 1.69 or 1.80 — and whether you want to upgrade an existing Sonnax planetary assembly or start from scratch. If you’re upgrading, you’ll need the big input shaft kit, stator tube kit and a rear sun gear kit. A brand-new build requires those three components plus a Sonnax planetary assembly and 27- or 32-spline output shaft.
Ask your performance parts distributor for Sonnax Powerglide big shaft system components or talk with a performance specialist about build options. For details on this and many more essential Powerglide upgrades from Sonnax, visit www.sonnax.com/powerglide.
This story was originally published on July 29, 2019. 
