🔩 Gear Coupling – Leyland L/L‑1616 / Cargo ZF (Square Type)

📌 What It Is

A gear box coupling flange is a drivetrain interface component fitted at the output of the ZF transmission on Leyland L/L‑1616, Cargo and similar models. Its role is to provide a mechanical connection between the gearbox output shaft and the propeller / driveline shaft while ensuring strong torque transfer and reducing backlash. The square‑type flange refers to the squared face profile of the coupling plate — often used in interaxle or ZF gearbox output applications where the mating yoke has a matching square interface.

📋 Typical Specification (Aftermarket Reference)

From parts catalogs covering commercial vehicle driveline components:

Feature	Details (Leyland L/L‑1616 / Cargo ZF)
Application	Leyland L/L‑1616, Cargo with ZF gearbox
Part Name	Gear Coupling / Gear Box Coupling Flange (Square Type)
Catalog Code	GC447 – Leyland 1616 / Cargo (ZF, Square Base)
Spline Count	28 splines (serrated/splined torque surface)
Plate Shape	Square coupling face (matches driveline yoke)
Bolt Holes	4 bolts – standard mounting pattern
Thickness / Height	~83 mm
Oil Seal Size (where applicable)	60 mm (on some variants)
Torque Class	Heavy‑duty truck application (ZF output)

📌 The GC447 entry in parts listings identifies this as the square‑type gear box coupling flange used on Leyland 1616 / Cargo with ZF gearbox setups.

🛠️ How It Works

⚙ Torque Transmission: Bolts to the ZF gearbox output flange and forms a positive engagement with the propeller shaft companion flange or interaxle shaft.
⚙ Serrated/Splined Interface: The 28‑spline (serrated) face ensures strong mechanical lock with the mating driveline part, minimizing slip under load.
⚙ Square Face Feature: The square profile provides anti‑rotation and consistent engagement geometry with travel/torque changes.

This setup is typically used where the driveline needs precise alignment and robust torque transfer between the gearbox and the propeller shaft or interaxle shaft — especially important in heavy‑load trucks like the L/L‑1616 and Cargo.

🚚 Where It’s Installed

In a Leyland L/L‑1616 / Cargo ZF drivetrain:

Engine → Clutch → ZF Gearbox Output → Square Gear Coupling Flange → Propeller Shaft / Interaxle Shaft → Differential → Wheels

The coupling flange bolts directly to the gearbox’s output and mates with the driveshaft yoke or intermediate shaft, forming the critical link that carries torque into the rest of the driveline.

🧠 Key Benefits

✔ Positive mechanical engagement with serrations/splines
✔ High torque capacity suitable for heavy‑duty truck use
✔ Square face helps maintain alignment and anti‑rotation
✔ Modular replacement — typically a bolt‑on part when servicing the driveline

📌 Summary

Gear Coupling – Leyland L/L‑1616 / Cargo (ZF, Square Type)