Finding a Replacement Clutch for a 1989 International S1654: Suppliers and Specs That Actually Work

ByWyatt Brooks

Finding a Clutch for a 1989 International S1600 / S1654

These trucks don’t get a lot of love at the auto parts counter, and that’s the whole problem. The International S-series sits in a tricky middle ground — too heavy-duty for a standard retail parts store, not common enough for most shops to stock on the shelf. The parts exist. You just need to know where to look and what specs to bring with you when you call.

Understanding the Platform

The 1989 International 1654 was sold as the S1654, part of International’s S-series medium-duty lineup. These were serious working trucks — utility fleets, municipalities, vocational haulers. High mileage and hard use were the norm, which means worn clutches are common and the aftermarket has had decades to fill the gap. The challenge is that most general-purpose parts stores don’t carry the commercial-grade line, so their computer coming up empty doesn’t mean the part doesn’t exist.

The 7.3-liter diesel in these trucks was a capable engine for its era. For clutch selection purposes, though, the engine matters less than what’s behind it. The transmission’s input shaft diameter and spline count are what determine which clutch kit fits — and that varies depending on which gearbox is installed.

Specs to Confirm Before You Order Anything

Ordering by year and model alone is asking for trouble with medium-duty trucks from this generation. Get the transmission identified first. The two most common clutch disc diameters for S-series medium-duty applications are 13 inches and 14 inches, with different spline configurations depending on the box.

Before calling any supplier, have these ready:

  • Clutch disc diameter — 13″ or 14″ is typical for this class of truck
  • Input shaft spline count — 10-spline is common in these applications
  • Input shaft diameter — 1-1/4″ and 1-1/2″ are the usual options
  • Flywheel condition — note whether it needs resurfacing, and whether the pilot bore is intact

A complete kit — pressure plate, clutch disc, release bearing, and pilot bearing — is the cleanest approach. Mixing components from different kits can create alignment headaches that shorten the new disc’s life fast.

Where to Actually Buy One

Phoenix Friction

This is the most direct route for S-series clutch kits. Phoenix Friction maintains a dedicated International/Navistar medium-duty section with kits catalogued specifically for IHC trucks. They list part numbers covering the common 13-inch and 14-inch configurations for these trucks, with organic friction material options. Call them with your transmission details and they can match you to the right kit. Straightforward and knowledgeable on this application.

NAPA Heavy Duty

NAPA carries parts specifically for the International S1654 through their heavy-duty catalog. Your local store may not stock it, but NAPA’s commercial network can order it. Pull up the S1654 listing on napaonline.com first to confirm availability and get a part number — that makes the counter conversation much faster.

Old International Truck Parts

OldInternationalTrucks.com is built around exactly this kind of hard-to-find IHC component. Their clutch section covers the Loadstar 1600 series and related S-series applications. Stock rotates, but they occasionally have NOS pieces that are simply gone from mainstream suppliers. Worth a look, especially if you need ancillary hardware like a clutch adjusting rod or linkage components at the same time.

Fort Wayne Clutch

Fort Wayne Clutch catalogs IHC/International clutch kits and covers models that the big chains routinely miss. They’re set up for commercial accounts, so turnaround tends to be quicker than chasing something through a general retailer’s back-order system.

eBay

Don’t overlook eBay. There’s a dedicated category for International Harvester truck clutch and drivetrain parts, and you’ll find both new aftermarket kits and used OEM components. Useful when a specific size or spline configuration is temporarily out of stock elsewhere.

CarParts.com

CarParts.com lists International clutch kits with free returns, which is useful if you’re not 100% certain on the spec and want a fallback option. Their catalog is worth cross-referencing against what the specialty suppliers show.

A Few Things Worth Knowing

When a parts store says “we don’t carry that,” they usually mean they don’t carry the commercial line — not that the part is unobtainable. Ask specifically for the heavy-duty or commercial department. Different catalog entirely.

Check the flywheel before the new clutch goes in. If it’s heat-checked, scored, or glazed, a new disc against it won’t last. A diesel-capable machine shop can resurface the flywheel while you’re waiting on parts — budget for it now rather than pulling the transmission twice.

Eaton offers a clutch selector tool on their website that’s handy for cross-referencing clutch specs against specific transmission models. Useful for confirming you’ve identified the right configuration before committing to an order.

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