3924466 3957598 Starter Motor （24V 5.5KW 10T 40MM） Fit for Cummins 6BT5.9 Engine

Product Overview

This starter motor (Reference No. 3924466 / 3957598) is a heavy-duty aftermarket replacement designed for Cummins 6BT5.9 (5.9L B-series) engine starting systems. It delivers stable cranking power to support reliable starts in construction equipment and industrial applications.

OEM Reference (For Identification Only)

Cummins lists Starting Motor 3957598 as used primarily on Tier 1 5.9 liter B engines. This product is an aftermarket replacement and is NOT a genuine Cummins part. OEM numbers are used for reference/identification only—please confirm fitment details before ordering.

Key Features

24V, high-torque starter motor for 5.9L B-series applications

Commonly listed as 5.5kW output class (ND/OSGR type in many catalogs)

10-tooth drive gear; gear outer diameter is commonly listed around 40–40.5mm (confirm with your original unit)

Durable construction for vibration, dust, and heavy-duty duty cycles

Typical Symptoms of a Failing Starter Motor

Slow cranking / intermittent starting

Clicking sound but engine does not turn over

Abnormal noise during cranking or starter overheating

Battery and alternator are normal but starting remains weak

Fitment Verification (Important)

To avoid mismatch, please confirm:

1. Engine model + engine serial number (6BT5.9)

2. Mounting bolt pattern and nose housing type

3. Pinion tooth count (10T) and pinion OD (~40mm)

4. Connector/terminal type and photos of the old starter (front + back + nameplate)

FAQ

Q1: Is this a genuine Cummins starter motor?

A: No. This is an aftermarket replacement. OEM part numbers are used for reference only.

Q2: How do I confirm it fits my Cummins 6BT5.9?

A: Please confirm engine serial number, mounting style, terminals/connector, and pinion specs (10T, ~40mm). Photos are strongly recommended.

Q3: What is the output?

A: Commonly listed as 24V 5.5kW class. Please refer to your original unit nameplate for exact rating.