Sonnax SmartShell Heavy Duty Reaction Shell Kit
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.
“Beast” or Reinforced SunShell
“The Beast” reaction sunshell by Proselect is one of the most popular upgrades for the GM overdrive 700R4 and 4L60E series transmission. This HD heat-treated unit is made of thicker steal than any factory unit, including the 4L65E-4L75E version. The drive shell comes with an updated durable nylon washer. This 100% genuine Pro-Select “The Beast” sun gear drive shell will work in either the earlier washer style or later Torrington bearing transmissions.
There are also many reinforced/heavy duty sunshells similar to the “Beast” sold online that achieve similar performance.
5 pinion front and rear planetary
This is a must for high HP, heavy abuse applications, and is highly recommended if you just want to increase the life or durability of any transmission. Upgrade your 4-pinion setup to this HD 5-pinion unit. This is one of the upgrades used in the 4L65-E transmission.
Most builders recommend used OEM planetaries from 4L65E over aftermarket ones. The decision is up to you.
4L60E Sonnax Heavy Duty Output Shaft
Output shaft failure is common as power levels are increased in GM 4L60-E, 4L65-E and 4L70-E units. Sonnax heavy duty output shaft 74678L-HD for 2WD and Corvette units is precision engineered and manufactured for unbeatable performance in high-horsepower street and strip builds. The shaft features many unique refinements available only from Sonnax, including a torsional design that allows energy to be absorbed, reducing peak loads to critical areas.
