A New Trick in the bag: additional second-gear servo size for the 4L60-E

GM has an additional second-gear servo size for the 4L60-E

For years we have known the 4L60 and 4L60-E 2nd gear servo came in three different sizes. Now there is a fourth OEM servo size that gives builders a new choice when looking for something with increased performance.

The 8642553 casting used in V6 and V8 applications is by far the most common size we see. However, if you are looking to add "a little extra" to a heavy duty rebuild and want a little more 2nd band apply area, but the Corvette or larger aftermarket servo are just too much for a daily driver, try the new 4L70-E servo. This is available from the dealer for about $40.00. You will need to order two part numbers, 24230441 piston & 24229157 divider/housing.

Compared to the Corvette servo, the 4L70-E servo is a modest increase in size over the V6/V8, 8642553 casting servo, and it will not change the shift feel as dramatically as a Corvette or a larger aftermarket servo would. There are plenty of options to change shift feel and upgrade this common transmission. This new 4L70-E servo is one more part you can add to your bag of tricks.

Gregg Nader is a Sonnax Technical Specialist and a member of the Sonnax TASC Force™ (Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax Industries Inc. technicians. Learn more about the group at www.sonnax.com/tasc_force.html.