Voltage drops and ECU faults often trace back to a failing alternator. This alternator assy cat 307d with 4m40tl engine 139-7850 is precision-built to OEM output specifications, delivering 14V/55A charging performance across all excavator operating loads — without the OEM price tag.

Why Choose This Alternator Assy Cat 307D With 4M40Tl Engine 139-7850
– Direct-fit replacement — correct pulley diameter, connector, and bracket mounting
– Brushless design rated for continuous operation up to +70°C
– Sealed bearing assembly with IP54 protection for dusty, wet site conditions

Heavy-Duty Construction
– Aluminium housing with heat fins keeps operating temperatures 15°C lower than standard
– Oxygen-free copper windings with Class H varnish insulation (180°C rated)
– Factory-tested at 3,000 RPM; ±2% output tolerance guaranteed

Maintenance Recommendations
– Temperature range: -20°C to +70°C
– Belt inspection every 500hrs — replace if voltage drops below 13.5V at idle
– Drop-in fit with OEM voltage regulator; no recalibration required
Australia-Wide Supply
We supply high-quality alternator assy cat 307d with 4m40tl engine 139-7850 replacement parts across Australia with shipping from NSW. Suitable for aftermarket heavy equipment repairs and undercarriage maintenance applications.