5th Input Gear for Manual Gearbox ⚙️

Why this part matters

This overdrive gear delivers quiet, low‑RPM cruising and better fuel economy on highways. In top gear it transfers torque from the input shaft to the countershaft, keeping the engine relaxed while maintaining steady speed and smooth acceleration.

How it works ?

Fitted on the input shaft, this helical, heat‑treated steel gear meshes with the counter gear and locks through the 5th synchronizer hub and sleeve. Accurate tooth geometry and proper oil film reduce friction and noise, while chamfers and lead‑in angles ensure clean, quick engagement.

When it’s worn or broken ?️

Symptoms include whine only in 5th, hard or crunchy shifts, gear pop‑out, vibration under load, and metal flakes in oil. Continued use can strip teeth, overheat synchros, damage bearings, and contaminate the whole gearbox—often ending in a costly rebuild and loss of 5th gear, with higher RPM and fuel use.

Tech tips ?

Replace related parts if needed (5th synchro ring, hub/sleeve, needle/roller bearing, snap rings). Set endplay and backlash correctly, torque to spec, and refill with GL‑4 oil only.

Compatibility

• Alto
• A-Star
• Celerio
• 800
• Fronte
• Cultus
• Splash
• Ritz