Symptoms:

  • C4 Clutch burned
  • 4th & 6th Gear shift concerns
  • Poor shift quality

Cause:

Wear on the I.D. of the sleeve prevents proper positioning of the inboard C4 relay valve.

Correction:

Sonnax drop-in C4 apply boost valve kit has upgraded materials and minimal clearances to prevent wear and restore proper hydraulic control.

UA80E, UA80F, UB80E, UB80F

C4 Apply Boost Valve Kit
Part No. 168740-02K

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

Vehicles with listed Toyota/Lexus transmissions may exhibit insufficient line rise in drive ranges 4th-6th Gears causing shift complaints and burnt C4 clutches. These problems may be caused by continuous oscillation of the C4 apply boost valve within the sleeve, creating excessive wear and a path for line pressure fluid to leak to exhaust. Sonnax C4 apply boost valve kit 168740-02K has upgraded materials and minimal clearances to prevent wear and restore proper hydraulic control.

  • Sleeve is manufactured from highly wear-resistant billet aluminum to prevent wear
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • UA80E, UA80F, UB80E, UB80F C4 Apply Boost Valve Kit 168740-02K
  • UA80E, UA80F, UB80E, UB80F C4 Apply Boost Valve Kit 168740-02K

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 C4 Apply Boost Valve Kit Vacuum Test Locations