In GM 4L60, 4L60-E, 4L65-E and 4L70-E units, 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 daily jobs to extreme builds, the Sonnax SmartShell heavy-duty reaction shell kit 77749-02K is the only way to prevent shell failure AND protect the bearing.
The SmartShell avoids the weight found in traditional, heavy-duty aftermarket shells thanks to a unique combination of improved design and manufacturing for a super strength shell
that's only slightly bulkier than OE.
To prevent thrust loads from overwhelming the captured planetary bearing, the SmartShell features a larger bearing and custom roller clutch race.
These parts re-route thrust loads through the carrier, completely bypassing the delicate bearing.