Doosan D913003 Nut-Lock Hor’ Ex Catalytic Muffler D60/70S5

Overview

The D913003 Nut-Lock-Hor’ Ex/ Hor’ Ex-w/Catalytic Muffler is an exhaust-system lock nut produced to the original Doosan specification for the D60/70S5 diesel forklift series. Its job is simple but critical: it clamps the horizontal exhaust and catalytic muffler assembly together so the joint stays sealed under constant vibration and repeated heat cycles. Exhaust fasteners work in one of the harshest areas of a forklift, where temperature swings gradually loosen ordinary hardware. When this nut wears or backs off, the result is often an exhaust leak, higher noise, and reduced catalytic muffler efficiency. Fitting the correct D913003 replacement restores a tight, secure connection.

Compatibility

This Doosan lock nut is listed for the D60/70S5 series (Tier3) and covers both transmission configurations of the platform:

• D60/70S5(2SPEED)(SB1112/D439E, Tier3)
• D60/70S5(3SPEED)(SB1113/D439E, Tier3)

Whether you need a D913003 for D60/70S5(2SPEED)(SB1112/D439E, Tier3) trucks or the 3-speed SB1113/D439E version, this part number covers both variants of the D60/70S5 range. Always double-check the model and serial plate on your truck, or send us the details and our team will confirm fitment before you order.

Quality and Reliability

The D913003 is manufactured to match the Doosan factory drawing, so the dimensions, thread form, and locking behavior line up with the original exhaust hardware on your truck. The nut is designed to hold its clamp load at the elevated temperatures typical of a Tier3 diesel exhaust fitted with a catalytic muffler, helping prevent the gradual loosening that leads to leaks and rattles. Choosing the specified part number instead of a generic fastener protects the muffler joints and keeps future servicing straightforward.

Installation and Maintenance Tips

• Always install a new lock nut; never reuse one that has been stretched or heat-cycled.
• Clean the stud or bolt threads and remove rust or old residue before assembly.
• Tighten to the torque value given in the Doosan service manual for your D60/70S5.
• Re-check the torque after the first hours of operation, once the exhaust has completed a full heat cycle.
• Inspect the muffler joint for soot marks or leaks during routine service and replace the nut at the first sign of loosening.

Why Order from Us

Forkliftpartssearch.com specializes in Doosan forklift parts, and our team knows how to match a part number to your exact truck configuration. Our catalog is organized by model and tier so you can find D60/70S5 components quickly, and our support staff can verify compatibility using your serial number. Order the D913003 Nut-Lock-Hor’ Ex/ Hor’ Ex-w/Catalytic Muffler here and get the correct hardware for your D60/70S5 forklift without guesswork.