• Direct clutch burned
  • Failed direct clutch
  • 2-3 Slide


Oil cross leakage at a worn accumulator piston bore pin.


The oversized accumulator pin allows the piston pin bore to be reamed to restore hydraulic integrity.

350, 350C

Oversized Accumulator Pin & Reamer Kit
Part No. 35718-02K

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A burned or complete failure of the direct clutch on the THM 350 transmission can be created by accumulator cross leaks. A drivability complaint of a long slide on the 2-3 shift can result from excessive piston wear. These complaints can be caused by oil cross leakage between the piston and pin in the front accumulator assembly located in the valve body. Excess wear is due to the constant oscillating motion of the the aluminum accumulator piston on the steel pin. The problem occurs when direct clutch oil and intermediate circuits cross leak. In second gear a cross leak may drag the direct clutch and create premature failure. Starter kit 34105-02K contains 10 pins, 10 retaining rings, and 1 reamer.

  • The working diameter of the pin is slightly oversized, allowing the bore of the accumulator piston to be modified to restore the hydraulic integrity of the assembly.
  • Kit contains an extra retaining clip to assist in holding the accumulator pin in the valve body, which is much less expensive than replacing the accumulator piston and more durable than a bushing.
  • Medium Retaining Rings (10)
  • Small Retaining Rings (10)
  • Pins (10)
  • Reamer
  • 350, 350C Oversized Accumulator Pin & Reamer Kit 35718-02K
  • 350, 350C Oversized Accumulator Pin & Reamer Kit 35718-02K details


Cleaning & Care Techniques for Sonnax Reamers