📌 What It Is
The differential coupling flange is a drivetrain component fitted at the rear axle/differential output of heavy commercial trucks like the Leyland L/L 2516 HT. This flange links the rear differential assembly to the propeller shaft companion flange, allowing torque from the differential to be transmitted to the driveshaft, and ultimately to the wheels, while also supporting proper lubrication sealing.
⚙️ Typical Specification & Function
Attribute
Specification / Function
Application
Leyland L/L 2516 HT heavy truck
Component Type
Differential Coupling Flange (Round, serrated/splined)
Plate Diameter
~175 mm (7″ class)
Spline Count
Commonly ~39 teeth — serrated torque surface
Bolt Holes
8 holes typical
Bolt Size
~9.50 mm / 15 No class
Approx. Height
~102 mm (HT ~102 mm) — overall flange thickness or extension length from differential output
Oil Seal Fitment
Typically matched to specific seal diameter (needs matching seal — not provided here)
📌 In aftermarket parts listings, Leyland diff couplings for the 7″ round type are commonly shown with 39 splines and 8 bolts, matching many 2516/2518 series differential outputs that use a 7″ plate series.
🔧 Role in the Drivetrain
The diff coupling flange on a heavy truck serves these key purposes:
✔ Torque Transfer: Provides a strong mechanical link between the axle differential’s pinion output and the propeller shaft, ensuring engine power is carried to the rear wheels.
✔ Positive Engagement: The serrated/splined face helps maintain positive engagement under variable load and torque conditions — critical for heavy trucks like L/L 2516 HT in haulage and load applications.
✔ Oil Seal & Protection: The flange typically works with an oil seal inside the differential housing to retain gear lubricant and keep contaminants out — improving service life of bearings and gears.
✔ Multi‑Bolt Safety: The 8‑bolt pattern ensures high security and durability under heavy torque conditions.
📍 Where It Fits
In the rear drivetrain of the Leyland L/L 2516 HT:
Transmission → Propeller Shaft → Differential Coupling Flange → Rear Differential → Axle Shafts → Wheels
The flange sits right at the rear differential output and acts as the mechanical join between the differential and the propeller shaft companion flange.
🛠️ Service & Replacement Tips
Always inspect the splines/serrations on both the flange and its mating companion flange when servicing — worn splines can cause driveline vibration or play.
Replace the oil seal whenever the diff coupling is serviced to prevent lubricant leakage.
Ensure proper torque on all bolts — loose or uneven torque can lead to misalignment or premature wear.
🧠 Summary
The differential coupling flange on a Leyland L/L 2516 HT truck (approx. 102 mm height) is a rugged, serrated (splined) round flange with multiple mounting holes that transmits torque from the rear differential to the propeller shaft and works with an appropriate oil seal to protect internal gears.