Sonnax #34672-05, TH400, 4L80E, 4L85E Extreme Duty Main Shaft.
Main shaft failure is a common problem in extreme duty TH400, 4L80E and 4L85E units. OE and aftermarket shafts simply don’t hold up in extreme horsepower applications, leading to spline twist and shaft breakage. Sonnax extreme duty main shaft 34672-05 is manufactured from an exceptionally tough high-strength steel alloy with proprietary heat treatment for unrivaled performance and durability. An advanced torsional design with spline and cross hole refinements make this the most durable 1″ main shaft available. Sonnax extreme duty main shaft withstood extensive in-vehicle and lab testing with unbroken results run after run.
- Top-notch engineering and precision manufacturing deliver unrivaled performance and durability in the 1” stock size
- Rear spline prevents the rear internal gear journal-end from twisting off by engaging the full internal spline of the gear
- Extensive in-vehicle and lab testing with unbroken performance
Can be used to replace late 4L80E and 4L85E solid shafts, however, check clearance between front of main shaft and rear of input shaft. It may be necessary to remove approximately .060″ from front of main shaft or rear of input shaft.
Extreme strength spline configuration requires use of thrust bearing between forward clutch hub and direct drum that moves support of forward clutch hub from the main shaft to the direct drum/sun gear tube (see instructions Figures 1 & 4).