GM Service Manual Online
For 1990-2009 cars only

Object Number: 31121  Size: SH

Using a feeler gage, measure the piston travel between the overrun clutch backing plate (510) and the overrun clutch backing plate retainer ring (511).

Piston Travel Specification
Piston travel should be 0.838-2.38 mm (0.033-0.094 in).