Function: Central torque distributor in Toyota/Lexus 6-speed FWD planetary gearset, enabling 5th/6th gear ratios.

Key Features:

• Material: Case-hardened alloy steel (HRC 58-62) with ground helical teeth

• Spline Design: Micro-polished internal splines for reduced wear against input shaft

• Thrust Control: Integrated washer surface (critical for axial play adjustment)

Failure Modes:

• Spline Stripping: Causes gear spin (sudden 5-6 shift flare, P2716 codes)

• Tooth Pitting: Fatigue from high-mileage overdrive use (whining noise)

• Bearing Surface Wear: Alters planetary alignment (>0.15mm wear = replace)

Critical Specs:

1. Sun gear axial play: 0.10-0.25mm (requires selective thrust washers)

2. Backlash with pinions: 0.07-0.13mm

Pro Tip: Always replace sun gear and planetary carrier as matched set – mismatched wear patterns cause premature failure.