SmartShell® Heavy-Duty Reaction Shell Kit fixes sun gear shell problems with BRAINS, not just brawn.

Bulky aftermarket shells always fall short when splines continue to strip and the shells break under stress. 

A chronic problem with both OE and thicker aftermarket shells is failure of the rear planetary bearing. 

From your daily jobs to extreme builds, the patented SmartShell is the only way to prevent shell failure AND protect the bearing.

Stripped or cracked shells in GM 700R4, 4L60, 4L60-E, 4L65-E and 4L70-E units are a common problem, but strengthening the shell alone does nothing to address the equally common problem of a failed rear planet captured bearing.