Product Description
**Milwaukee parts change not only by model# but also by serial number. To look up your tools parts break down on Milwaukee's website please click here:
Milwaukee Lock On-Off Shuttle
Model Number: 42-42-0037
The Milwaukee 42-42-0037 Lock On-Off Shuttle is a genuine OEM replacement part designed for use across the Milwaukee 2646 M18 Cordless Grease Gun platforms, including the 2646-20 bare tool, the 2646-21CT kit, and the 2646-22CT 2-battery kit configurations. Identified as Figure 8 on Milwaukee service bulletin 54-06-2630 dated October 2022, the lock on-off shuttle is the small precision sliding mechanism integrated into the trigger assembly that lets the operator lock the grease gun trigger in the ON position for continuous, hands-free dispensing during extended lubrication work, then unlock and release the trigger to stop dispensing. This lock-on feature is essential for high-volume grease gun work such as lubricating multi-grease-fitting equipment, heavy machinery, agricultural and industrial equipment, or any application where holding the trigger continuously would cause operator fatigue.
A worn, broken, or deformed lock on-off shuttle prevents the trigger from locking in the ON position, causes the lock to disengage unexpectedly during use, or prevents the trigger from releasing properly when the lock is disengaged. These symptoms make the grease gun's signature lock-on feature unreliable and force the operator to hold the trigger manually for every dispensing cycle. Replacing the shuttle with this OEM service part restores correct lock-on operation, reliable lock disengagement, and full trigger function. The Lock On-Off Shuttle works in conjunction with the Milwaukee 40-50-0890 Spring (Figure 5 on the same bulletin), and Milwaukee's documentation specifies two of those springs per grease gun working with the shuttle and the adjacent Switch Trigger (Milwaukee 45-72-0088) to deliver the correct mechanical engagement and detent action. Because Milwaukee Tool specifies replacement parts by both catalog number and serial number, always verify your tool's serial number against the official Milwaukee 2646-20 service parts diagram before ordering, since Milwaukee occasionally implements running production changes that affect part compatibility within the same catalog number. Verify by serial number using Milwaukee's online parts lookup before ordering to confirm correct fitment.
Features
- Genuine Milwaukee OEM replacement, direct factory part for the 42-42-0037 reference
- Designed for the Milwaukee 2646-20, 2646-21CT, and 2646-22CT M18 Cordless Grease Guns
- Lock on-off mechanism sliding shuttle for the trigger assembly
- Locks the grease gun trigger in the ON position for continuous, hands-free dispensing
- Essential for high-volume grease gun work and multi-fitting lubrication routines
- Works with the Milwaukee 40-50-0890 Spring (Fig 5) and Switch Trigger (45-72-0088)
- Manufactured to Milwaukee factory tolerances and dimensional specifications
- Direct-fit replacement, no modification required for installation
- Restores correct lock-on and lock-off operation after wear, breakage, or deformation
- Documented in Milwaukee service bulletin 54-06-2630 (October 2022), Figure 8
Specifications
- Manufacturer: Milwaukee Tool
- Part Number: 42-42-0037
- Official Description: Lock On-Off Shuttle
- Component Type: Trigger Lock-On Mechanism Shuttle
- Confirmed Compatible Models: 2646-20 M18 Cordless Grease Gun, 2646-21CT M18 Grease Gun Kit, 2646-22CT M18 Grease Gun 2-Battery Kit
- Service Bulletin Reference: 54-06-2630 (October 2022), Figure 8
- Companion Service Parts: Milwaukee 40-50-0890 Spring (2 per tool), 45-72-0088 Switch Trigger - all sold separately
- Quantity: Sold individually, 1 shuttle per order
- Part Type: OEM Service Replacement Part
Includes
- (1) Milwaukee 42-42-0037 Lock On-Off Shuttle
- Note: Companion service parts (Milwaukee 40-50-0890 Spring, 45-72-0088 Switch Trigger) are NOT included and sold separately. Recommended for inspection and replacement at the same time during a full trigger assembly service
- Note: Verify your tool's catalog number (2646-20, 2646-21CT, or 2646-22CT) and serial number against the official Milwaukee parts diagram before ordering
