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  • Loss of lubrication oil to planetaries
  • Reverse drum, retainer & planet failure


Excessive clearance between the overdrive piston retainer and intermediate shaft reduces lube flow to the gear train.


Seal compensates for variations in case I.D. Oil is delivered to maximum load points on shaft. Optional oversized reverse drum journal allows salvage of reverse drum.

42RE, 42RH

Oversized Piston Retainer Kit
Part No. 12962N-02K

Upgraded sealing ring & oil flow

View Instructions

Sonnax is now offering an upgraded standard replacement 12962N-01K and an oversized 12962N-02K piston retainer to allow rebuilders to salvage the expensive reverse drum. The oversized piston retainer requires only turning the I.D. of the drum using a lathe and then installing as normal.

  • Can be used in hydraulic or electonicly governed units
  • O-ring prevents loss of lube oil. Many OE supports do not seal well in this area.
  • Two O.D. oil delivery grooves have been repositioned at high load areas.
  • Two I.D. oil delivery grooves run full length of load-bearing surface.
  • Band drum diameter (standard and oversized) allows drum I.D. to be turned.
  • High-quality aluminum resists gauling.

Allows damaged reverse drum to be machined and salvaged.

  • Piston Retainer
  • O-Ring
  • Plugs (2)

  • 12962n 02k alt
  • 12962n 02k combo
  • 12962n 02k