Typical Defects in Parking Rod Manufacturing and Countermeasures

■ What Is a Parking Rod?
A parking rod is a critical safety component in the parking lock mechanism of automatic transmission (AT) vehicles. It operates the parking pawl via the shift lever to securely hold the vehicle in the P range. Even minor shape or surface defects can cause poor locking performance, abnormal noise, or AT malfunction.
■ Applications
Parking rods are used in parking lock mechanisms of AT vehicles. Rod geometry and cam angle vary by vehicle model, and the parts are installed in AT units for mini vehicles, passenger cars, and trucks.
■ Typical Defects
Foreign material contamination (chips, lint) – May damage the parking lock gear and cause vehicle immobilization.
Dimensional errors – Prevent proper assembly with the manual valve lever and may block engagement of the P range.
Cam damage, burrs, or improper pin angle – Cause poor movement and shift lever malfunction.
Bending defects or uneven hardening – Lead to stress concentration and possible rod breakage.
Assembly or welding defects – May result in loss of parking lock function, especially on slopes.
■ Preventive Measures
Control glove replacement, cleaning solution condition, and implement strict 2S in welding processes.
Regularly inspect jigs, reference positions, and measuring equipment.
Standardize handling and deburring methods.
Inspect bent areas by comparison with approved samples.
Use visual controls to prevent assembly errors.
Verify inspection equipment accuracy and perform full weld inspections.
■ Key Points for Customers
As a safety-critical component, parking rods require clear specification at the ordering stage:
Tolerances for dimensions, cam angle, and R geometry
End-face finishing requirements
Bending evaluation methods
Foreign material control standards
Welding specifications
Assembly orientation and identification
Inspection items and frequency
■ Ohashi Tekko Vietnam’s Strengths
Ohashi Tekko Vietnam specializes in mass production of shafts and rods, with integrated capabilities for bending and end-face finishing. By applying Japanese quality standards, improving jigs, and standardizing processes, the company delivers stable, high-quality parking rods with minimized defect risk.
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