Dual seals stabilize and completely seal the bore, providing a tight seal even after thousands of cycles.. Pinless design eliminates the possibility of pin leakage, and the additional length stabilizes the piston to prevent piston cocking.. 3 x Aluminum pistons, 6 x seals, 6 x Steel balls. 2 for the 1-2 accum/3-4 accum and the other for the Forward Accumulator.. In GM 4L60-E, 4L65-E and 4L70-E units it is common for the plastic forward accumulator piston to wear or crack. This causes a loss of fluid, resulting in delayed engagement, slips, burnt clutches and/or bands. This pinless forward accumulator piston kit 77987-01K eliminates these problems.. In GM units it is common to have poor shift quality, burnt bands or clutches due to accumulator piston wear. Repeated reciprocation of the accumulator piston causes wear at the piston pin bore interface. After this wear reaches a critical point, fluid loss through the piston pin bore cannot be compensated due to lack of pump volume.To prevent these conditions in the 1-2 or 3-4 accumulator bores, this offers pinless accumulator piston kit 77998-03K..
