Product Overview
The N375865 Gear Assembly is a precision-engineered direct-fit transmission replacement for 18V cordless hammer drills built on this common platform. This complete gear assembly (listed as “GEAR SA” in OEM parts diagrams, item #19) includes the full gear train components – eliminating the need for individual gear diagnosis and piecemeal replacement.[reference:8][reference:9]
Designed for professional repair technicians and equipment maintenance specialists, this gear assembly restores factory-spec performance to tools exhibiting grinding noises, loss of torque under load, or failure of the hammer action mechanism. The heavy-duty metal construction delivers the durability required for continuous hammer drilling into concrete, masonry, and steel.[reference:10]
N375865 is an active OEM part number with no substitutes listed, confirming its status as the current-spec replacement for this gear assembly across compatible platforms.[reference:11]
💡 Pro Tip – Pre-Installation Diagnostic: Before tearing into the gear case, perform a simple test. With the battery removed, rotate the chuck by hand through the full speed range. A smooth rotation with positive detent engagement indicates the gear train is intact. Any grinding, binding, or uneven resistance points to gear tooth damage or bearing failure – both resolved by this N375865 gear assembly replacement. Also inspect the shifter assembly (N375867) and baffle assembly (N375868) for wear while the gear case is open.[reference:12][reference:13] Always remove the battery pack before beginning disassembly.
Diagnostic & Fitment – When to Replace
Specification Comparison
| Specification | Worn / Generic Aftermarket | FixPartHub Precision Replacement ✅ |
|---|---|---|
| Gear Material | Low-grade steel or sintered metal | Precision-cut alloy steel – heavy-duty metal construction[reference:14] |
| Hammer Action Performance | Inconsistent or non-functional | Full OEM-spec hammer action restored[reference:15] |
| Torque Transmission | Power loss under load | Full torque delivery – OEM-spec[reference:16] |
| Fitment Guarantee | Vague or incorrect compatibility claims | Direct-fit for DCD996 / DCD995 / DCD991 / DCD990 / DCD992[reference:17] |
| Part Number Status | Discontinued or generic cross-reference | Active OEM part number – no substitutes[reference:18] |
Teardown & Replacement Workflow
Compatibility – Cross-Reference & OEM Part Numbers
Diagnostic Q&A
❓ Q: My drill makes a grinding noise but still spins – do I need to replace the entire gear assembly?
A: Yes. Grinding noise indicates tooth wear or pitting in the gear train. While the drill may still function, the damage will progressively worsen until the gear assembly fails completely – often at the worst possible moment. Replacing the complete N375865 gear assembly now prevents catastrophic failure and potential damage to the motor and other components.[reference:21]
❓ Q: What models are compatible with the N375865 gear assembly?
A: This gear assembly is compatible with DCD996, DCD996B, DCD996BR, DCD996P2, DCD995, DCD995B, DCD991, DCD991B, DCD991P2, DCD990, DCD990M2, DCD992, DCD992N, and DCD998W1R models.[reference:22][reference:23][reference:24] Always verify your tool’s model number against the compatibility list before ordering.
❓ Q: Is N375865 the correct replacement part number for my drill?
A: N375865 is the active OEM part number for the gear assembly (referenced as “GEAR SA” in OEM parts diagrams). It has no substitutes listed and is the current-spec replacement across compatible platforms.[reference:25][reference:26] This listing supplies the N375865 assembly, which is the correct replacement for all compatible models.
❓ Q: What other components should I inspect when replacing the gear assembly?
A: While the gear case is open, inspect the shifter assembly (N375867), baffle assembly (N375868), and gearcase assembly (N470330) for wear.[reference:27][reference:28][reference:29] Also check the anvil (N481809) and the motor pinion gear.[reference:30] Replace any worn components simultaneously to ensure full transmission performance.
Safety Notes
- 🔴 Always remove the battery pack before beginning any disassembly or gear replacement procedure.
- ⚡ Allow the tool to cool completely before handling internal components – gear cases can reach high temperatures during hammer drilling operations.
- 🔧 Use correct torque values – gear case screws (N042665) typically require 1.5–2.0 Nm (13–18 in-lbs). Over-torquing can strip housing threads or distort the gear case alignment.[reference:31]
- 🧤 Wear appropriate PPE – safety glasses and cut-resistant gloves when handling gears and metal components.
- 📐 Verify gear mesh before final assembly – the transmission should shift smoothly between speeds with positive detent engagement.
- ✅ Perform a no-load test before reinstalling the chuck – verify smooth operation across all speed ranges and correct hammer action function.
A: Perform a manual rotation test with the battery removed. Rotate the chuck by hand through all speed ranges. Smooth, consistent rotation indicates the gear train is intact. Any grinding, binding, uneven resistance, or complete seizure indicates gear tooth damage or bearing failure – requiring replacement of the N375865 gear assembly. Additionally, listen for grinding or whining noises during operation under load – this indicates active tooth wear.
A: Yes. N375865 is the OEM gear assembly for DCD996, DCD995, DCD991, DCD990, and DCD992 platforms. It is referenced as item #19 (“GEAR SA”) in OEM parts diagrams for all these models. This is the correct direct-fit replacement across all compatible variants.
A: N375865 is the primary gear assembly (“GEAR SA”) – the main transmission gear component. Other part numbers in the same drill include N481798 (a secondary gear assembly) and N375867 (shifter assembly). N375865 is the primary gear that drives the hammer mechanism and torque transmission.
A: The N375865 is a complete gear assembly – it includes the primary gear train components. However, it’s recommended to inspect the shifter assembly (N375867), baffle assembly (N375868), and gearcase assembly (N470330) for wear while the gear case is open. Also apply fresh Molykote grease (N017298) during reassembly.
