GMC M340 Parts & Accessories

GMC M340 Parts & Accessories

The GMC M340 is a medium-duty chassis application that served commercial and fleet operators requiring a purpose-built work vehicle beyond the capability of the standard light-duty lineup. Like other GMC medium-duty platforms, the M340 features heavier axle and brake hardware scaled to its payload class, making application-specific replacement parts critical for proper safety and performance. These vehicles were commonly fitted with utility bodies, stake beds, or specialty conversions for service industries, and their mechanical durability has allowed many examples to accumulate high mileage in daily commercial use. Operators maintaining these vehicles today rely on accurate part sourcing to keep them productive.

Popular Upgrades

Brake system maintenance is the priority service for the M340, with Raybestos, Bendix, and StopTech offering replacement drum shoe kits, wheel cylinders, and master cylinder rebuild components for this commercial chassis. AC Delco fuel pump and carburetor kits address the most common engine drivability concerns on the inline-six and V8 engines used in this class. Gates belt kits cover timing and accessory drive systems for all engine options. Monroe and Gabriel replacement shocks restore the front suspension control that deteriorates under years of loaded daily commercial operation.

Performance and Handling

The GMC M340's suspension and steering components are specified for commercial payload loads and must be replaced with components rated for the chassis GVWR rather than passenger car equivalents. Moog replacement steering components including tie rod ends and center link restore the precise steering feel required for safe commercial vehicle operation. Rear spring replacement from National Spring or equivalent suppliers restores the payload capacity and ride height lost to fatigued leaf springs on high-mileage fleet examples.

What engine does the GMC M340 use?

The GMC M340 was typically equipped with inline-six or V8 gasoline engines common to the medium-duty GMC lineup of its era, with specific displacement varying by production year and application. AC Delco and Holley supply replacement carburetor and fuel system components for these engines, while ARP and Clevite cover the internal engine rebuild hardware. Confirming the engine code from the VIN tag before ordering ensures you receive components sized for your specific engine family rather than a close but incompatible variant.

How do I order the correct brake parts for a GMC M340?

Brake parts for the GMC M340 should be ordered using the chassis code and GVWR from the door jamb certification plate rather than year and model alone, as brake hardware sizing on medium-duty platforms varies significantly by configuration. Raybestos and Bendix both publish medium-duty brake catalogs that cross-reference by chassis code, axle rating, and drum diameter. Ordering in this manner prevents the common fitment error of receiving passenger car or light-truck brake components that will not clear the larger drum diameters on this platform.

Why These Parts Fit Right

Parts in this collection are matched to the GMC M340's commercial chassis specifications, ensuring brake, suspension, and drivetrain components meet the payload-class requirements of this vehicle. Fast shipping gets commercial operators back in service quickly, and expert support is available to confirm the correct part for any specific year and configuration. Accurate commercial vehicle application data means your parts arrive ready to install.

GMC commercial vehicle owners also browse our exhaust components, suspension parts and shocks, and air intake and filtration upgrades.