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  • Output & reaction planet assembly wear
  • Output and planet assembly failure


Extended normal service, abusive service and/or no aftermarket components are available.


This kit includes all the components needed to rebuild damaged output and reaction planet assemblies, and also gives technicians the option of replacing only the worn components. Planet gears are not included and not currently available.

4L80-E, 4L85-E

Planetary Rebuild Kit
Part No. 34880RK

Output & reaction planetaries, 1999 & Later

The output and reaction planetary pinion assemblies in '99-later 4L80-E transmissions frequently wear out and must be rebuilt or replaced. New replacement assemblies can be costly and the availability of quality aftermarket assembly components is limited. Sonnax offers a replacementparts kit 34880RK, which contains all the components needed to rebuild all four planet pinions in a single output or reaction carrier (planet gears not included). Individual components may also be purchased separately.

  • Kit restores proper operational clearances for worn or failed planet assemblies.
  • Kit allows for complete rebuild of all the planet assemblies in a carrier.
  • Individual components allow technicians to replace only the visibly worn components.

Fits '99-later units with wider planet gears. This application can be identified by its planet gear width of .816; a needle roller length of .804; and the PTFE-coated bimetal symmetric thrust washers.

  • Pinion Pins (4)
  • Needle Rollers (72)
  • Washers (8) Round
  • Batwing Thrust Washers (8)
  • 34880rk