KAIDA KDJY100 10 ton 4×4 mining forklift
Fault Description
A Chinese wheel loader arrived at the workshop with the following symptoms:
- Engine running normally
- Hydraulic lifting system operating correctly
- Travel speed significantly reduced
- Poor climbing ability
- Insufficient traction under load
- Machine unable to achieve normal driving performance
Since the hydraulic system was functioning properly, the initial diagnosis focused on the power transmission system.
Preliminary Inspection
Technicians first checked:
- Transmission oil level
- Transmission oil condition
- Gear shifting operation
- Drive shafts and axles
No obvious abnormalities were found.
The machine was then tested in both high gear and low gear. Even in low gear, which should provide maximum traction and torque, the loader still exhibited weak travel performance.
Based on these findings, the fault was suspected to be located between the engine and transmission.
Cause Analysis
Further inspection indicated possible damage to the torque converter coupling, commonly referred to as the steel wheel or coupler.
The torque converter is responsible for transferring engine power to the transmission. When the coupling becomes worn, cracked, or damaged, power transfer efficiency decreases significantly.
Typical symptoms include:
- High engine RPM with poor machine movement
- Reduced driving force
- Transmission slipping under load
- Difficulty climbing slopes
- Metal debris present in transmission oil
Repair Procedure
Step 1: Separate Engine and Transmission
The engine was removed to gain access to the torque converter assembly.
After disconnecting the engine from the transmission housing, the torque converter components were inspected.
Step 2: Inspect and Replace the Coupling
Inspection revealed severe damage and wear to the torque converter coupling.
The damaged component was removed and replaced with a new coupling assembly.
All mounting surfaces and related components were checked before reassembly.
Step 3: Clean the Torque Converter
During disassembly, a considerable amount of metal contamination was found inside the torque converter.
The contamination included:
- Iron particles
- Steel fragments
- Aluminum debris
To prevent secondary damage, the torque converter housing and oil passages were thoroughly cleaned.
Step 4: Replace Transmission Oil
After cleaning, new transmission oil was added according to the manufacturer's specifications.
Fresh oil helps eliminate residual contaminants and ensures proper lubrication of the transmission system.
How to Identify a Damaged Coupling
One of the most reliable indicators of coupling failure is inspection of the transmission filter screen.
If the filter screen contains:
- Large iron particles
- Metal flakes
- Excessive metallic sludge
there is a strong possibility that the coupling or other transmission components are experiencing abnormal wear.
Regular inspection of transmission oil and filter screens can help detect problems before major failures occur.
Repair Result
After replacing the damaged coupling, cleaning the torque converter, and installing fresh transmission oil, the machine was tested again.
The results showed:
- Normal travel speed restored
- Improved traction and climbing performance
- Stable transmission operation
- Full recovery of driving power
The loader returned to service with normal operating performance.
Maintenance Recommendation
Many Chinese wheel loaders and 4x4 rough terrain forklifts are equipped with both high-speed and low-speed travel ranges.
A common operating mistake is using high gear during heavy-duty work such as:
- Loading gravel
- Pushing material
- Climbing steep grades
- Operating on muddy or rough terrain
- Carrying heavy loads
High gear is intended primarily for transportation and road travel.
Using high gear under heavy load increases stress on the torque converter and coupling, resulting in:
- Excessive heat generation
- Increased internal slipping
- Accelerated component wear
- Reduced service life of the coupling
For maximum transmission life, operators should use low gear whenever high torque is required and reserve high gear for light-load travel.
Spare Parts Support
We supply replacement parts for Chinese wheel loaders and rough terrain forklifts, including:
If your machine experiences weak travel power, transmission slipping, or abnormal metal contamination in transmission oil, please contact our technical team for troubleshooting assistance and replacement parts support.
Website: www.aforklift.com
Email: neil.zhou@aforklift.com
WhatsApp: +8618660028237
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