Symptoms:

  • Worn accumulator piston pin bore
  • Damage from broken spring
  • 4-3 Kickdown
  • 2-3 Soft
  • 3rd Clutch distress

Cause:

Normal wear and uneven loading from spring.

Correction:

Install the Sonnax replacement piston with increased bore length for more piston-to-pin support and greater durability

4T80-E

3-4 Accumulator Piston
Part No. 72872-01

Find a Distributor

The piston bore in 4T80-E units is prone to wear, either through normal operation or uneven loading from the spring. The Sonnax replacement piston 72871-01 provides more piston-to-pin support and greater durability than OE replacements.

  • Increased bore length for more piston-to-pin support
  • Machined from high-quality aluminum
  • More durable than OE replacements
  • Piston accepts standard OE or replacement seals

This piston should not be used in a first-design 2-3 accumulator found in '93 models. These units do NOT have the second bumper spring on the top portion of the accumulator piston. If the large spring is broken, replace with GM part number 8684828

  • 4T80-E 3-4 Accumulator Piston 72872-01
  • 4T80-E 3-4 Accumulator Piston 72872-01