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  • B1 Clutch burned
  • Poor shift quality
  • Engine braking concerns
  • 5th Slip
  • 3rd Slip


OE B1 apply control plunger sleeve deterioration allows pressure loss that leads to drivability concerns.


Recover hydraulic control and renew shift performance by installing Sonnax B1 apply control plunger kit.

A750E, A750F

B1 Apply Control Plunger Kit
Part No. 147741-55K

You need this if... View Instructions

Toyota/Lexus vehicles equipped with A750E and A750F transmissions may exhibit 5th Gear complaints and a burnt B1 brake as well as low line pressure, resulting in poor shift quality and slipping in Forward or Reverse. These issues can often be traced to wear in the OE B1 apply control plunger sleeve, which allows line pressure to escape and cause drivability concerns.

Installing Sonnax B1 apply control plunger kit 147741-55K eliminates pressure loss, revives B1 apply pressure control and restores shift quality.

  • Sleeve manufactured from highly wear-resistant aluminum
  • Hardcoat anodized aluminum valve combats premature wear
  • Annular groove helps center valve in sleeve to reduce side-load wear
  • Valve
  • Sleeve
  • 147741 55k combo
  • 147741 55k

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.

  • 147741 55k in test