🔩 Pinion Coupling – Eicher 10.90

A pinion coupling is a drivetrain component used to connect the pinion shaft (input side of the differential) to the driveshaft or companion flange inside the rear axle assembly of a truck. Its primary role is to transmit torque smoothly from the driveline into the final‑drive pinion gear, which then drives the crown wheel and axle shafts to propel the vehicle.

📌 Application — Eicher 10.90

Designed for the Eicher 10.90 truck family — a BS‑IV‑era light/medium commercial vehicle chassis used in buses and goods carriers with about 107 HP diesel engine and 5‑speed gearbox.
In parts catalogs, you’ll find pinion coupling items listed specifically for Eicher 10.90 drivetrains indicating its use in propeller shaft/differential interface assemblies.

⚙️ Function & Importance

📍 What the Pinion Coupling Does

Connects the propeller/driveshaft to the rear axle pinion gear input inside the differential housing.
Helps ensure accurate torque transfer and gear alignment between the driveline and final drive.
Reduces drivetrain noise and vibration by maintaining solid engagement between splined or serrated mating surfaces.

📍 Typical Location
Placed within or near the rear axle / differential housing, between the driveshaft companion flange and the pinion gear input.

🛠️ Design Notes

Often constructed from high‑strength alloy steel to withstand torsional and shock loads from the engine and gearbox.
May include splines or serrated faces to mate securely with the differential and companion flange.
Works with associated bearings and seals inside the axle housing to protect the differential and maintain lubrication.

Related parts in Eicher 10.90 driveline assemblies include:

Gearbox coupling flanges
Centre joints / couplings
Propeller shaft yokes
Pinion bearings / sleeves
These support the pinion coupling in transferring power to the final drive.

📌 Parts Catalog References

Parts listings for Eicher 10.90 identify specific pinion coupling part codes, such as: