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  • Case damage
  • Worn accumulator bores
  • Scored accumulator bores


Repeated oscillation of the accumulator piston scores the 3-4 accumulator bore during normal operation.


This simple drop-in solution comes with an aluminum sleeve, a replacement piston with an O-ring, and a new accumulator pin. It is compatible with all OE accumulator springs.

4L60, 4L60-E, 4L65-E, 4L70-E

3-4 Accumulator Sleeve Kit
Part No. 77998-01K

View Instructions

The 3-4 accumulator bore on GM 4L60 and 4L60-E series cases can become scored, resulting in the loss of 4th servo feed and 4th accumulator pressure. Scoring is caused by repeated oscillation of the accumulator piston within the bore during normal operation. Once this bore is damaged the case must be scrapped. Sonnax 3-4 accumulator sleeve kit 77998-01K conteracts bore wear and features upgraded materials for greater durability. The kit's piston is compatible with all OE accumulator springs.

  • Sleeve is manufactured from wear-resistant aluminum
  • Requires no machining of the transmission case
  • Repair Sleeve
  • Piston
  • O-Ring Fluorocarbon
  • Accumulator Pin
  • 77998 01k