• Poor shift quality
  • Pressure loss
  • Various concerns depending on location of leaking end plug


Worn, eroded end plugs allow loss of critical hydraulic pressure.


Sonnax drop-in O-ringed end plugs restore correct circuit pressures. The O-ring provides additional sealing to reduce hydraulic losses at critical circuits.

UA80E, UA80F, UB80E, UB80F

O-Ringed End Plug Kit
Part No. 168740-10K

You need this if... View Instructions Find a Distributor

The primary design function of the OE end plug in listed Toyota/Lexus transmissions is to prevent critical pressure loss by capping the bore. OE end plugs rely entirely on small clearances between the end plug and bore to confine hydraulic fluid under fluctuating pressure. End plugs are often tasked with a secondary role functioning as a spring stop or valve stop.

The repetitious and varying actions of fluid pressure, spring motion and valve impact cause wear at the end plug and bore mating surface and can distort the shape of the end plug. High-pressure fluid leaking through the clearance gap can, with time, erode the surface material of both end plug and bore. Eventually the cumulative loss of hydraulic integrity leads to low pressure in critical circuits. Complaints vary depending on the location of the worn end plug but are always related to pressure losses.

Sonnax O-ringed end plug kit 168740-10K replaces worn, distorted or eroded end plugs in Toyota/Lexus UA80E/F and UB80E/F series transmissions. Sonnax end plugs have an O-ring seal that reduces leakage further by blocking off worn areas of the bore which the new end plug alone could not seal.

  • Minimal end plug-to-bore clearance with added O-ring for positive seal
  • Drop-in Zip Valve parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • End Plug Large
  • O-Rings (2) Large, 1 Extra
  • End Plugs (3) Small
  • O-Rings (6) Small, 3 Extra
  • UA80E, UA80F, UB80E, UB80F O-Ringed End Plug Kit 168740-10K
  • UA80E, UA80F, UB80E, UB80F O-Ringed End Plug Kit 168740-10K

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

UA80E, UA80F, UB80E, UB80F O-Ringed End Plug Kit Vacuum Test Locations