Sonnax 77998-03K Pinless Accumulator Piston Kit 4L60 1-2 / 3-4

The Sonnax 77998-03K is a pinless accumulator piston kit for 4L60 automatic transmissions. It replaces the factory accumulator piston, which can wear at the pin bore and cause poor shift quality and burnt clutches and bands. The kit is made for the 1-2 or 3-4 accumulator bores.

Key Features:

• Sonnax patented pinless design removes the need for the pins and the possibility of pin bore leakage.
• The extra piston length stabilizes the piston in the bore and helps prevent piston cocking and bore galling.
• Dual seals stabilize the piston and seal the bore, and they keep sealing after thousands of cycles.
• Steel balls plug the existing pin bore in the case or cover.

Kit Contents:

• Pinless accumulator piston (aluminum)
• D-ring (Viton®)
• Seal (PTFE)
• Steel ball, .312" dia.
• Steel ball, .236" dia.

Note: in 200-4R applications, this kit can only be used in the 3-4 accumulator location.