CROSS MEMBERS & MOUNTS

Cross Members & Mounts For Peterbilt Trucks

Frame cross members and component mounting brackets are the structural backbone that keeps a truck's body, drivetrain, and cab components properly supported and aligned. On high-mileage trucks operating in harsh conditions, cross members can crack from fatigue or corrode to the point of failure. We carry replacement cross members and mounting hardware for Peterbilt trucks to restore structural integrity and keep components properly positioned.

Frequently asked questions about cross members & mounts

How do I know if a frame cross member is cracked or damaged on my Peterbilt?

Visible cracks in cross members often appear at weld joints and fastener holes — high-stress concentration points. Signs of a compromised cross member include unusual frame flex, alignment issues that recur after correction, and vibration or noise that changes with load. A thorough frame inspection under the truck, ideally with the truck loaded to working weight, is the most reliable way to identify cross member damage. Cracks should be addressed promptly since they propagate under load.

Can frame cross members be repaired, or do they need to be replaced?

Minor cracks in cross members can sometimes be repaired by welding, but frame repair on a commercial truck is governed by FMCSA regulations and should only be performed by a qualified shop using approved methods. Repairs on load-bearing structural components require proper weld procedures and materials to restore original strength. For severely damaged or heavily corroded cross members, replacement is generally the more reliable and compliant solution.

How are engine and transmission mounts related to cross members?

Engine and transmission mounts attach the powertrain to the frame cross members, using rubber isolators to absorb vibration and prevent it from transferring into the cab. Worn rubber mounts allow excessive powertrain movement, which can cause driveline vibration, alignment issues, and accelerated wear on connected components. Cross member condition directly affects mount performance — a distorted cross member changes the mount geometry and can cause premature mount failure.

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