For fleet operators and heavy-duty logistics companies, the SINOTRUK HOWO transmission (typically the HW19710 or HW15710 series) is the literal workhorse of the drivetrain. While these 10-speed and 12-speed gearboxes are designed for extreme loads, poor maintenance or incorrect operation can lead to catastrophic failures. In this 2026 technical guide, JINAN ARCHER TRADE CO.,LTD analyzes the most frequent transmission issues and provides actionable maintenance strategies.
01 / Abnormal Noise: Identifying Gear and Bearing Wear
Whining or grinding sounds during gear changes are the first warning signs of internal distress. This is often caused by the degradation of the gear oil, leading to metal-on-metal contact between the sun gears and planet gears. In the HOWO HW series, bearing failure in the auxiliary box can cause a distinct rumbling sound at high speeds. Early intervention—replacing worn bearings before they seize—can save the entire gear set.
02 / Gear Slipping: Synchronizer and Selector Issues
If your HOWO truck jumps out of gear under load, the culprit is usually a worn synchronizer ring or a misaligned gear selector fork. Over time, the locking teeth on the synchronizer hub lose their edge, failing to maintain a secure lock. JINAN ARCHER TRADE CO.,LTD recommends a full inspection of the auxiliary box synchronizer if jumping occurs specifically when switching between high and low ranges.
03 / Difficult Shifting: Air System and Clutch Linkage
Difficulty engaging gears often stems from the pneumatic system rather than the mechanical gearbox itself. HOWO transmissions rely on air pressure to assist in range shifting. Leaks in the air cylinder or a faulty solenoid valve can make shifting feel “heavy” or impossible. Always verify that your system pressure is between 0.7 and 0.8 MPa before diagnosing internal mechanical failures.
04 / Overheating: Oil Level and Cooling Integrity
Heat is the enemy of transmission longevity. If your HOWO gearbox is running hot (above 100°C), check for overfilled or underfilled oil levels. Excessive oil causes foaming and aeration, which reduces cooling efficiency. Furthermore, ensure the external oil cooler (if equipped) is free of debris. Using genuine 85W-90 GL-5 gear oil is mandatory for maintaining the correct viscosity under African and Middle Eastern thermal conditions.
05 / Sourcing Strategy: Genuine Parts for Transmission Overhauls
When a failure occurs, the quality of the replacement parts determines how long the truck stays on the road. Counterfeit synchronizers and bearings are rampant in the aftermarket. At JINAN ARCHER TRADE CO.,LTD, we supply 100% genuine SINOTRUK transmission components with factory-certified dimensions and metallurgy. Don’t risk a second failure by choosing sub-standard parts.
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