[clinebarger]

2-4 Servo Assembly.

I'm going to start with 2nd gear Piston sizes, Identification, And what it means.

In the industry we use the last 3 Digits of the 2nd Piston part number for identification.

554 Piston. Has the Smallest Apply Area, Has the Weakest clamping force on the Band, Used on 4 & 6 cylinder applications. DO NOT USE behind a V8!!!

553 Piston. A little more Apply Area & Band holding power, The most common V8 & 4.3L V6 700R4 2nd piston, Great behind stock to mild engines & people that do not want a Firm 1-2 shift.

159 Piston. Again, More Apply Area. Used in 4L70E's ONLY as far as I know. Really nice 1-2 & 2-3 shifts. If you like cleaner shifts a little Firmer than stock....This is the one.

093 Piston. AKA "Vette Servo Piston", Has the greatest Apply Area, Almost Ridiculous really, The 1-2 will end up Very Firm after the Band seats in.
More of a "patch" for a New Band on an Worn Reverse Input Drum, Does produce the Cleanest 2-3 shift