Peterbilt 567/579 Frame Crossmembers & Covers

Frequently Asked Questions About Peterbilt 567/579 Frame Crossmembers & Covers

What do frame crossmembers and covers actually do on my Peterbilt 567 or 579?

Frame crossmembers are structural components that run horizontally between the frame rails, adding rigidity to the chassis and providing mounting points for components like the fuel tanks, battery boxes, and fifth wheel. Covers are typically installed over or around these crossmembers to protect them from road debris, moisture, and corrosion while also giving the underside of the truck a cleaner, finished appearance.

Will these crossmembers and covers fit both the Peterbilt 567 and 579 models?

Many parts in this category are designed to fit both the 567 and 579 due to shared frame architecture, but exact fitment can vary depending on the model year, frame length, and factory configuration of your specific truck. We recommend checking the part listing details and cross-referencing your VIN or OEM part number before purchasing to confirm a proper fit.

What materials are these crossmembers and covers made from, and how well do they hold up?

Crossmembers are typically made from heavy-gauge steel to match OEM strength requirements, while covers may be steel, aluminum, or diamond-plate depending on the specific product. Steel components are often coated or painted to resist rust and corrosion, but as with any underbody part, regular inspection and cleaning will help extend their service life, especially in regions with heavy road salt or moisture exposure.

Do I need to remove other components to install a replacement crossmember or cover?

In most cases, yes. Installing a replacement crossmember often requires supporting the frame, removing fasteners connecting it to the frame rails, and disconnecting any brackets or lines that run through or near it. Covers are generally more straightforward and may only require removing a few bolts or clips. Because crossmembers are structural, we recommend having installation performed by someone familiar with heavy-duty truck frame work or referring to Peterbilt service documentation for your specific model.

Are these replacement parts OEM Peterbilt parts, or aftermarket alternatives?

This category includes both genuine Peterbilt OEM parts and quality aftermarket options. OEM parts are built to match factory specifications exactly, while aftermarket alternatives can offer a cost-effective option that still meets the fit and function needs of your truck. Product listings will specify whether an item is OEM or aftermarket so you can choose based on your budget and preference.