TowWorks Trailer Hitch Locking Pin 5/8" x 4-1/2" Keyed-Unique for 3" Receivers — Anti-Rattle, Tubular Push-Lock

TowWorks 79831 is an extra-long 5/8" diameter trailer hitch locking pin with a 4-1/2" active span, built to secure adjustable channel-style hitches and 3" receivers with a keyed-unique tubular lock.

Whether you're towing heavy equipment or simply parking your trailer, the right locking pin keeps your hitch and cargo secure. The TowWorks 79831 combines an extended steel pin, anti-rattle rubber O-rings, a push-lock tubular mechanism with dust protection, and an independent spring clip for added redundancy. It’s sized to work with many popular adjustable hitch and pintle hook assemblies — just confirm measurements before ordering.

Will this hitch lock fit my adjustable channel-style hitch?

The 79831 is designed with a 5/8" diameter and a maximum active length of 4-1/2", matching many adjustable channel hitches such as specific CURT models and several adjustable pintle hooks. It does not fit every brand — for example, it is not compatible with FASTWAY adjustable hitches — so measuring your receiver and channel width is essential.

• Pin diameter: 5/8" (0.625")
• Maximum active span: 4-1/2" (114.3 mm)
• Commonly fits CURT channel-style adjustable hitches 45900, 45901, 45902
• Incompatible with FASTWAY adjustable hitches — verify dimensions first

How does the lock stop rattles and protect the mechanism?

TowWorks includes rubber O-rings that compress to remove play between the pin and receiver tube, cutting down noise and vibration during travel. The lock barrel has a watertight dust rubber cap to shield the tubular lock from moisture and grit, helping maintain smooth operation over time.

• Rubber O-rings reduce movement and road noise
• Watertight rubber cap prevents internal corrosion of the lock
• Adjustable O-ring quantity lets you fine-tune fit for different tube tolerances

What security features does this pin include?

The 79831 uses a tubular push-lock mechanism with a quarter-turn action for quick locking and unlocking. Each unit ships keyed unique — two tubular keys are included — and a separate spring clip (cotter pin) is supplied for redundant mechanical retention, which must be installed when using the lock for safety.

• Keyed unique tubular lock for individualized security
• Two tubular keys included for convenience
• Separate spring clip (cotter pin) provides backup retention
• Push-lock and quarter-turn operation for fast use

How do I ensure a proper fit before buying?

Measure the inside width of your adjustable channel or receiver tube and the distance the pin needs to span. Compare those numbers with the 5/8" diameter and 4-1/2" maximum active length; adjust or remove O-rings if necessary for a snug fit. If you need multiple locks keyed alike, choose the alternate TowWorks SKU that offers keyed-alike options.

• Measure receiver/channel inside width and required pin span
• Confirm pin diameter 5/8" matches your hitch hole
• Remove or add O-rings to eliminate play if required
• Order SKU 79830 for multiple locks keyed alike

Who this is for: The TowWorks 79831 is intended for trailer owners, contractors, and fleet managers who use adjustable channel-style hitches or pintle hooks and need a heavier-duty, extra-long locking pin. It suits users who want a compact tubular lock with anti-rattle features and a redundant cotter-pin option — provided they confirm fit dimensions first.