🔩 Gear Coupling (Gear Box Coupling Flange) – Leyland L/L 350 & L/L 370 (Tusker)
📌 What It Is
The gear coupling (sometimes called gear box coupling flange) on a Leyland Tusker series truck is a torque‑transmitting flange fitted at the gearbox output. It connects the gearbox to the propeller shaft companion flange via a serrated or splined face so that rotational power from the transmission is passed reliably into the driveline with minimal slip or backlash. The serrations (teeth) on the flange provide positive engagement with the mating yoke or flange.
⚙️ Typical Specification
According to commercial vehicle aftermarket parts catalogs:
Application: Leyland L/L 350 & L/L 370 Tusker trucks — gear box coupling / gear coupling flange.
Shape & Type: Round serrated flange (mechanical coupling face with teeth).
Plate Diameter: ~146 mm — common size for this coupling.
Number of Splines/Teeth: 6 splines/teeth on the serrated face.
No. of Holes: 4 bolt holes for secure mounting to the gearbox output shaft flange.
Bolt Size/Thickness: Typically around 21 mm bolt hole size with ~12.80 mm plate thickness.
OEM Reference: Often referenced by part code F1431022 (or similar) in spare parts listings for Leyland Tusker coupling flanges.
👉 In price list catalogs this part often appears as:
“Gear Coupling – L/L 350/370 Tusker, Round” with ~6 splines and 4 bolts.
🛠️ Function in the Drivetrain
This gear coupling flange is located on the output end of the gearbox and serves to:
✔ Transmit torque from the gearbox output shaft to the propeller shaft/yoke
✔ Provide positive mechanical engagement with serrations/splines to resist slip under load
✔ Maintain alignment between gearbox and driveshaft to reduce vibration and drivetrain wear
✔ Facilitate easy assembly and disassembly when servicing the driveline