Gearbox Leaking Fluid: Causes, Fixes, and When to Replace
A gearbox leaking fluid is one of the most common and costly issues in industrial equipment. Whether in a reducer, gearbox drive, or gear motor, a fluid leak can lead to overheating, gear wear, system failure, and expensive downtime.
In this guide, we’ll explain why gearboxes leak, how to troubleshoot the problem, and when it’s time to repair or replace the unit.
Why Is Your Gearbox Leaking Fluid?
There are three major reasons for fluid leaks in gearboxes:
🔧 1. Worn or Damaged Seals
Shaft seals and gaskets break down over time due to friction, pressure, and contamination. A small crack in a seal can lead to major oil leakage.
Signs: Oil around shaft or seal area, drips below unit
Solution: Replace the seal or gasket with OEM-quality components
🔩 2. Overfilled Gearbox or High Internal Pressure
Too much oil or blocked breather vents cause pressure buildup, forcing oil past seals.
Signs: Fluid leaks from top or breather, wet casing
Solution: Drain to proper oil level; clean or replace breather
🧱 3. Housing or Shaft Damage
A cracked gearbox housing or bent shaft can misalign components and cause leaks.
Signs: Uneven wear, noises, visible cracks
Solution: Disassemble and inspect. Severe cases require rebuild or replacement.
How to Fix a Gearbox Leak
The following table provides five steps to help you troubleshoot your leaking gearbox.
| Step | Action | Description |
|---|---|---|
| 1️⃣ | Identify the Source | Clean unit, run under load, and observe where oil is escaping |
| 2️⃣ | Check Oil Level | Drain excess oil or refill to correct level per spec sheet |
| 3️⃣ | Inspect Seals | Look for wear or contamination; replace if needed |
| 4️⃣ | Clean or Replace Breather | Blocked vents can cause pressure buildup |
| 5️⃣ | Monitor After Fix | Run unit again to confirm leak is stopped |
Should You Repair or Replace a Leaking Gearbox?
✅ Repair if:
Leak is small and from a single seal
Gears and shafts are still in good condition
Unit has low hours or is high-value
❌ Replace if:
Housing is cracked or corroded
Internal gears show pitting or wear
Unit is obsolete or poorly supported
Preventing Gearbox Fluid Leaks
Regularly inspect seals, vents, and mounting points
Keep breather vents clean and functional
Use the correct lubricant type and amount
Monitor temperature and vibration for early warning signs
Expert Tip:
Leaking gearboxes can ruin surrounding components. Oil contaminates belts, motors, and production surfaces. Always address leaks immediately to avoid system-wide damage.
Get Fast Help for Leaking Gearboxes
Industrial Gearbox Supply specializes in:
Emergency gearbox repair
In-stock replacements
Reverse-engineering and seal replacement
Drop-in interchange services for obsolete units
📞 (517) 858-2966
📧 sales@industrialgearboxsupply.com
🌐 www.industrialgearboxsupply.com
🏢 3590 Scheele Dr, Jackson, MI 49202