Camshaft Gear 3946436 for Cummins 4B3.9–QSB5.9 & Hyundai HL757-7 – Direct Replacement

Product Specifications

Compatible Models

Struggling with Timing Gear Failure on Cummins QSB5.9 or Hyundai HL757-7 Engines?

One failed camshaft gear can halt loader operations for days — costing $2,500+ per day in downtime, labor, and missed deadlines. Many buyers receive counterfeit 3946436 camshaft gears that wear out within 300 operating hours, causing misalignment, valve train damage, and costly secondary repairs. OEM parts often require 3–4 weeks lead time and carry a 40% price premium over verified aftermarket alternatives.

OEM-Equivalent Quality, In Stock & Ready to Ship

This camshaft gear 3946436 is engineered to meet original Cummins and Hyundai timing specifications, manufactured in ISO 9001-certified facilities with full incoming material inspection and pre-shipment performance testing. Used in field-replacement engine rebuilds for Hyundai HL757-7 loaders and Cummins QSB5.9-powered equipment, it delivers reliable synchronization under continuous high-torque load cycles — without waiting weeks or paying OEM markup.

Where This Part Works

This camshaft gear operates in high-duty-cycle environments: quarry loading, port container handling, municipal earthmoving, and demolition site support. It transmits precise rotational timing between crankshaft and camshaft at up to 2,800 RPM under variable load, maintaining valve lift accuracy critical for emissions compliance and fuel efficiency. A mismatched or low-grade gear risks timing drift, combustion inefficiency, and premature cylinder head gasket failure — especially in hot, dusty, or humid conditions common across Southeast Asia, the Middle East, and Latin America.

Engineering Details That Matter

Made from SAE 1045 forged steel with induction-hardened teeth (HRC 52–56), this gear resists pitting and micro-cracking under repeated impact loads. Its tooth profile follows AGMA Class 12 tolerances for backlash control — ensuring less than 0.05 mm deviation versus OEM specs to prevent gear rattle and vibration. The hub features precision-machined interference fit geometry for secure mounting on the camshaft journal, eliminating slippage during cold starts or sudden torque spikes. Surface black oxide treatment provides ISO 9223 Class C3 corrosion resistance — validated in 96-hour salt-spray testing — essential for coastal port and mining applications.

The Real Cost of Wrong Parts

A $45 counterfeit camshaft gear may seem economical — but it typically fails before 500 operating hours, triggering $1,200+ in labor to re-open the timing case, replace damaged followers or lifters, and recalibrate injection timing. Industry data shows incorrect 3946436 camshaft gear replacement increases total cost of ownership (TCO) by 3.2× over 2,000 hours due to unplanned downtime, secondary damage, and warranty voids. Genuine OEM-equivalent parts like this one maintain ISO 8573-1 air cleanliness compliance in the timing cavity and uphold Cummins QSB5.9 engine service intervals — protecting your long-term investment.

Why Customers Trust XUNPO

Packaging & Shipping

• Individually sealed in rigid cardboard box with EPE foam inserts and VCI anti-corrosion paper
• In-stock items ship within 2–5 working days after payment confirmation
• Flexible logistics: DHL/FedEx/UPS express (3–7 days), air freight (7–12 days), sea freight (25–40 days)
• Real-time tracking number provided upon dispatch, updated until final delivery
• MOQ is 1 piece — designed for emergency maintenance and small-batch fleet servicing

Get Your Camshaft Gear Replacement Today

Your loader or excavator isn’t generating revenue while idle — every hour counts. Send us your machine model (e.g., HL757-7 or QSB5.9), quantity needed, and destination country, and we’ll email a competitive quote within 24 hours. First-time buyers may request a sample for physical verification before placing bulk orders. No registration or minimum commitment required.

Frequently Asked Questions