Kenworth T680 and W900 Shocks: Which Monroe Magnum Fits

The Short Answer

For a 2013–2024 Kenworth T680, Monroe makes dedicated Magnum shocks for both the front and rear axle positions — each with a 1.75-inch bore diameter — but fitment depends on your suspension type, so confirm before you order.

If you're replacing shocks on a T680 or W900 and wondering whether Monroe has the right part — yes, they do. The question is *which one*, and that's what this guide settles. ---

Why the Monroe Magnum Line Exists for Heavy Trucks

Monroe's Magnum line launched in 2018, consolidating what had been a fragmented lineup of heavy-duty commercial products under a single global brand. The goal was straightforward: one name, clear fitment, purpose-built for Class 3–8 trucks, fleet vehicles, emergency apparatus, and severe-use applications. The flagship variant for air-suspended Class 8 trucks is the Monroe Gas-Magnum 65 — described by Monroe as the first gas-charged, large-bore shock specifically engineered for air spring and taper leaf suspensions. It uses a nitrogen gas charge to produce faster damping response compared to traditional hydraulic designs. That matters when you're running 80,000 lbs down an interstate that hasn't seen a repaving crew since the Obama administration. Monroe itself sits within Tenneco's DRiV division. Tenneco is privately held, owned by Apollo Global Management following their acquisition in November 2022. The brand's commercial truck heritage runs deep — that's not marketing copy, it's why fleet managers keep specifying it. ---

Kenworth T680 Shocks: Front vs. Rear Fitment

Rear Position (2013–2024 T680)

The rear Monroe Magnum for the T680 is the one most owners need first. It's designed specifically for trucks running the Air Glide 400L Air Suspension — Kenworth's standard rear air setup on most T680 configurations. The 1.75-inch bore diameter gives it more fluid volume than a typical light-truck shock, which translates to better heat management on long-haul routes. This shock replaces OE part numbers C711017 and C711011. If your truck has one of those on it now, the Monroe Magnum is a verified direct replacement. Coverage runs through 2024 model year T680s. ### Front Position (2013–2020 T680)

The front Monroe Magnum carries the same 1.75-inch bore diameter. Coverage on this one runs 2013–2020 T680s. If your truck is a 2021 or newer, use the part finder to confirm the current front fitment — Monroe's lineup has evolved and you want the right part, not the close one. One thing worth saying plainly: front shocks on a Class 8 truck affect steering feedback. A worn front shock on a T680 doesn't just make the ride rough — it makes lane changes and crosswind correction less predictable. Don't put the front off because "it's not as bad as the rear."

Kenworth W900 Shocks: What's Different

The W900 is a different animal from the T680. It's a conventional (long-hood) truck, generally running a solid front axle rather than the T680's independent front setup, and suspension configurations vary significantly across model years. Monroe's Magnum line does cover W900 applications — the Class 3–8 scope is wide — but there's no single universal answer here. What to know going in:

• W900 production spans several decades with meaningful suspension changes along the way
• Front axle type (solid vs. independent) changes shock geometry and mount style
• Rear suspension setup (leaf spring vs. air) determines which Magnum variant applies

My honest take: the W900 is the truck where you *really* need to run the part finder rather than guess. I've seen owners order "a Magnum" without specifying the suspension, then deal with a return and a week of downtime. Thirty seconds in the finder saves that. ---

What the 1.75-Inch Bore Diameter Actually Means

Both T680 Magnum shocks — front and rear — use a 1.75-inch bore diameter. Here's why that number matters and why Monroe chose it for this application:

• More bore = more fluid volume — larger pistons move more hydraulic fluid per stroke, which spreads heat across a larger area
• Better fade resistance — heavy trucks load their shocks far harder than passenger cars; a shock that fades under sustained load is a safety issue, not just a comfort issue
• Nitrogen gas charge — in the Gas-Magnum 65, the nitrogen charge prevents aeration (foaming of hydraulic fluid), which is what causes that mushy, imprecise feel after hard use

For context, a typical passenger car shock runs a bore of around 1.0–1.2 inches. The jump to 1.75 inches isn't incremental — it's a fundamentally different component for a fundamentally different workload. ---

Signs Your T680 or W900 Shocks Need Replacing

You don't need a shop to tell you these:

• Oil weeping or active leaking from the shock body — this one's definitive, replace immediately
• Cab bounce that doesn't settle after a bump or dip — two or more oscillations means the damping is gone
• Cupped tire wear — uneven scalloping around the tread is a classic symptom of worn shocks on a drive axle
• Steering wander or crosswind sensitivity — mostly a front shock symptom, often misattributed to alignment
• Nose dive under braking — the front shocks aren't just for comfort; they're part of your stopping geometry

Most commercial fleets inspect shocks every 100,000–150,000 miles, but conditions vary enormously. A truck running smooth interstates in Arizona and a truck hammering logging roads in the Pacific Northwest aren't on the same replacement cycle. ---

Replacing in Pairs: Why It's Not Optional on a Class 8

Replace shocks in axle pairs — both fronts or both rears at the same time. This isn't a light-truck guideline being applied to a big truck; it's more critical here. A T680 with one new rear Magnum and one worn-out original will have asymmetric damping across the drive axle. At 65 mph with a full load, that imbalance affects load transfer and handling stability in ways that aren't theoretical. The cost difference between replacing one and replacing two is small relative to the labor already being done. Do both. ---

Monroe Magnum vs. Running Your T680 on Worn Shocks

"A worn shock on a fully loaded Class 8 increases stopping distance, accelerates tire wear, and puts additional stress on frame and suspension components — the savings from delaying replacement are almost always smaller than the costs downstream."

That's not hyperbole. Worn shocks on a heavy truck have documented effects on braking performance. Monroe's Magnum line — nitrogen-charged, large-bore, purpose-built — is a practical answer to that problem for Kenworth operators. It's not the cheapest option on the market, and Monroe doesn't pretend it is. It's the one engineered for this class of truck. Use the finder below to confirm exact fitment for your year, position, and suspension type, and to see current pricing. ---

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