Genie 990170GT Nylon Insert Lock Nut, 3/8

The Genie 990170GT is a genuine OEM Nylon Insert Lock Nut, 3/8 built for Genie and Terex portable light towers, including the AL4000, AL5000, AL5HT, AL5 with Vertical Mast, and RL4. As a direct OEM replacement, this fastener is manufactured to the exact specification Genie requires, ensuring the correct thread engagement and retention force for the application. Cross-reference part number 990170GT against your machine's parts manual to confirm it is the right fit for your unit before ordering.

Key Features

• Genuine OEM Fastener Grade — Manufactured to Genie's dimensional and material standards, with a nylon insert sized and rated to match the original 3/8 specification.
• Direct OEM Replacement — Installs exactly as the original, with no modification to the fastener point or mating hardware required.
• Broad Light Tower Fitment — Fits multiple Genie and Terex portable light tower models, including the AL4000, AL5000, AL5HT, AL5 with Vertical Mast, and RL4 series.
• Vibration-Resistant Locking Action — The nylon insert grips the thread after installation, resisting loosening from vibration and operational movement so the fastened joint stays secure over time.
• Correct Part, First Time — Sourced directly from Genie's OEM supply chain, so the thread pitch, insert material.

A nylon insert lock nut uses a non-threaded nylon collar at the top of the nut that deforms around the bolt thread when driven into place, creating a friction lock that resists loosening under vibration and repeated load cycles. Unlike standard hex nuts, the nylon insert provides a secondary retention force that keeps the joint clamped even when the assembly is subject to movement or engine vibration — common conditions on portable light tower equipment. A worn or missing lock nut allows fastened joints to back off gradually, which can lead to misalignment, structural looseness, or component separation that interrupts machine operation.

Part Details

Compatibility & Fitment

Verify Before You Order

Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.

Why Buy From DHS Equipment

Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.

Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.