Peterbilt 357/378 Drive Axle Springs & Hangers

Frequently Asked Questions About Peterbilt 357/378 Drive Axle Springs & Hangers

What do drive axle springs and hangers actually do on my Peterbilt 357/378?

Drive axle springs and hangers are part of your truck's suspension system. The springs support the weight of the vehicle and its load while absorbing road shock, and the hangers are the mounting brackets that attach the springs to the frame rail, keeping the axle properly positioned. Together, they play a key role in ride quality, load distribution, and overall handling stability.

How do I know if I need new springs, hangers, or both?

Common signs that these components need attention include visible cracks or sagging in the leaf springs, uneven ride height, excessive bouncing or body roll, unusual noises like clunking or squeaking over bumps, and visible rust, wear, or looseness around the hanger brackets and bushings. If you notice any of these issues, it's a good idea to have the suspension inspected to determine whether the springs, hangers, or both need to be replaced.

Will these springs and hangers fit my specific Peterbilt 357 or 378 configuration?

Peterbilt 357 and 378 models were built with a variety of suspension setups depending on axle capacity, spring configuration, and model year, so fitment can vary. Before ordering, check your truck's build sheet or existing components for part numbers, spring capacity ratings, and hanger style to confirm compatibility. If you're unsure, our team can help you verify fitment using your VIN or existing part numbers.

Are these components sold individually or as a complete set?

Availability depends on the specific part. Some items, like individual leaf springs or single hangers, are sold separately, while others may be offered as kits that include matched springs, hangers, and mounting hardware. Check the product listing details for what's included, and reach out if you need help determining exactly what you'll need for a full suspension repair.

What should I know about installation before I order?

Replacing drive axle springs and hangers typically involves supporting and lifting the vehicle, removing the axle assembly or disconnecting it from the suspension, and unbolting the worn components before installing the new ones with proper torque specifications. This is a heavy-duty job that often requires shop equipment like a lift and proper safety supports, so many customers have this work performed by a qualified truck repair shop. Always follow Peterbilt's service manual torque and alignment specifications to ensure safe, proper installation.