99-06 Chevy/GMC Silverado Sierra Weld-On Under Bed C-Notch Kit – Up to 6" Drop

Drop your rear 5–6 inches without the axle eating your frame.

Once you go past 4” in the rear on a 99-06 GMT800, your rear axle will contact the frame under compression — every hard bump, every speed bump, every dip. It’s not a question of if. This C-notch gives your axle the clearance it needs, welded into the frame rail using a slip-over design that self-centers on the factory rail so you’re not measuring and fighting to get it positioned.

3/16” steel. Under-bed placement. Pre-bent bottom cap included. Fits every cab and bed combo — regular, extended, crew.

Key Features

• Fits: 1999–2006 Chevy Silverado & GMC Sierra — All cab and bed styles
• Drop: Allows up to 6" of rear suspension drop
• Material: Heavy-duty 3/16" steel construction
• Professionally welded for superior strength and consistency
• Slip-over frame design — slides directly over factory frame rails for a perfect, centered fit every time
• Includes pre-bent bottom cap — simply cut, drop in, and weld
• Bare metal finish — ready for primer, paint, or undercoating to match your build
• Under bed placement preserves bed floor integrity

How It Installs

1. Slip the notch over the factory frame rail
2. Weld it into position
3. Cut out the bottom section of the frame
4. Weld on the included pre-bent bottom cap
5. Perfectly centered — no measuring required

Professional welding experience and proper fabrication tools required. Not a bolt-on kit.

Install Video: https://youtu.be/zXZpeThJb5Y?si=PixLdhRn0HtC1uim

Specs

Completing your rear drop?

A C-notch handles axle clearance — but a full 5–6” rear drop also needs:

∙ Drop hangers and/or shackles
∙ Flip kit
∙ Pinion angle correction (skip this and you’ll have driveshaft vibration at highway speed)
∙ Shock extenders

Contact us if you want help building the full rear setup for your build.

⚠️ Liability Disclaimer

This product is intended for off-road use and show vehicle applications only unless installed by a certified professional welder and fabricator in accordance with all applicable federal, state, and local laws and regulations. Modification of your vehicle's frame is a significant structural alteration. Improper installation may result in serious injury, death, or property damage. The manufacturer and seller assume no responsibility or liability for improper installation, misuse, or any damages, injuries, or losses — direct or indirect — resulting from the use of this product. By purchasing this product, the buyer accepts full responsibility for installation, use, and compliance with all applicable laws. Always consult a qualified professional before modifying your vehicle's suspension or frame.