What are the lubrication points of synchromesh gearbox?

In a synchromesh gearbox, proper lubrication is critical because it has many moving parts that experience friction, load, and heat. Lubrication ensures smooth gear engagement, long life of gears, synchronizer rings, and bearings.

Here are the key lubrication points:

**lubrication points of synchromesh gearbox?**

1️⃣ Gears

Constant mesh gears on layshaft and main shaft.
Purpose: reduce friction, prevent wear on gear teeth.
Lubrication: Gear oil flows over teeth during operation.

2️⃣ Synchronizer Rings (Synchro Rings)

Friction surfaces of synchromesh rings match speed of gear and shaft.
Purpose: ensure smooth gear engagement, reduce wear on conical surfaces.
Lubrication: Requires thin film of gear oil; too much oil can reduce friction and cause slipping.

3️⃣ Sliding Dog Clutches / Collars

The dog teeth that engage gears are in direct contact with main shaft gears.
Purpose: allow gear selection without sticking or wear.
Lubrication: Oil prevents metal-to-metal wear and corrosion.

4️⃣ Bearings

Input shaft, layshaft, main shaft, and output shaft bearings.
Purpose: reduce friction and handle radial/axial loads.
Lubrication: Gear oil keeps bearings running smoothly and cool.

5️⃣ Shift Forks / Sliding Collar Mechanism

Shift forks move dog clutches along the main shaft.
Purpose: enable smooth movement for gear engagement.
Lubrication: Light coating of gear oil prevents sticking and wear.

6️⃣ Reverse Idler Gear

Engages only for reverse gear.
Purpose: reverse rotation of main shaft.
Lubrication: Oil on gear teeth and shaft prevents wear during engagement.

✅ Lubrication Method

Splash lubrication: Oil inside the gearbox is splashed by rotating gears onto all moving parts.
Fill level: Gearbox has a specified oil level to ensure all parts are submerged or splashed adequately.
Oil Type: Typically high-quality manual transmission oil, rated for pressure and load (e.g., SAE 75W-90 GL-4/GL-5).