• Soft shifts
  • No 2nd
  • No 3rd
  • No 4th
  • Premature clutch failure


OE accumulator control valves restrict oil flow to clutches due to interference from ridges that form in the bore. Symptoms appear when valve hangs up on ridges.


Use Sonnax bore sizing tool to remove wear ridges, smooth and resize the bore to prevent valve hang-up.

4R100, E4OD

Bore Sizing Tool
Part No. 36948-12

View Instructions Find a Distributor

Sonnax bore sizing tool 36948-12 smooths and deburrs accumulator control valve bores to permit salvage of accumulator bodies. This tool allows the bore to be properly resized to prevent hang-up of Sonnax valves.

  • Prepares bore for installation of Sonnax performance rated accumulator spring kit 36948-18K and installation of OE accumulator control valves and Sonnax accumulator control valve kits 36948-09K and 36948-13K
  • 4R100, E4OD Bore Sizing Tool 36948-12