✅ Coupling Drive Pinion — Pinion Coupling / Drive Pinion (General)
A pinion coupling (sometimes called a pinion drive coupling or coupling flange) is a drivetrain component used in rear‑drive vehicles like the Ashok Leyland Dost to connect the propeller (driveshaft) to the final drive / differential assembly.
What It Is:
It’s essentially a splined flange‑type connection mounted on the end of the rear differential pinion shaft or the companion driveline shaft.
The mating splines/teeth on the coupling match the corresponding splines on the shaft it attaches to, creating a secure mechanical engagement that transmits torque.
Function & Role:
Power Transmission: It transfers rotational force (engine torque) from the propeller shaft into the rear axle differential / pinion gear so the wheels can be driven.
Secure Connection: The splined interface ensures a tight fit, handling rotational loads without slipping while the vehicle is in motion.
Alignment & Load Bearing: The flange design helps keep the driveline aligned and balanced, reducing vibration and wear on nearby drivetrain parts.
Where It Fits:
Installed between the propeller shaft/companion shaft and the rear differential pinion input, the pinion coupling allows a robust connection that transmits torque efficiently from gearbox to axle.
In simple terms, the pinion coupling on a Leyland Dost is the part that links the rotating propeller shaft with the rear differential pinion, enabling smooth and reliable power delivery to the rear wheels.