• Pressure loss
  • TCC apply concerns
  • Burnt clutches
  • Harsh shifts
  • Soft shifts


Damaged, deformed and/or eroded end plugs and bores allow loss of critical hydraulic pressure.


Recover hydraulic control and renew crucial circuit pressures by installing Sonnax drop-in O-ringed end plug kit.

4L80-E, 4L85-E

O-Ringed End Plug Kit
Part No. 34200-05K

TCC & PR Valves

Find a Distributor

OE end plugs are designed to prevent critical pressure loss by capping the bore, while also functioning as a valve stop. Repetitive spring motion, valve impact and fluid pressure variations cause wear between the end plug and bore mating surface, allowing vital pressure to escape the circuit. GM 4L80-E and 4L85-E pumps have end plugs at the pressure regulator and TCC shift valves that seal signal oil required to stroke the valve. When excess wear occurs at the end plugs, the result can be shifting problems, loss of gear and/or converter-related concerns.

Stop leaks and revive line pressure and TCC operation by installing Sonnax O-ringed end plug kit 34200-05K.

  • Minimal end-plug-to-bore clearance with added O-ring for positive seal
  • Reduces or eliminates leakage in eroded OE bores
  • Drop-in Zip Valve parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • End Plugs (5)
  • O-Rings (5)
  • Dia.: 0.625"

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

GM 4L80-E, 4L85-E, TH400 Valve Body Layout

GM 4L80-E, 4L85-E, TH400 Valve Body Layout
  • 4L80-E, 4L85-E O-Ringed End Plug Kit 34200-05K