| International S series | |
|---|---|
 1989 Navistar International S-1700 dual-axle dump truck | |
| Overview | |
| Manufacturer |
|
| Also called | Navistar International 4000 series Navistar International 8000 series |
| Production |
|
| Body and chassis | |
| Class | Class 6-7 medium-duty truck |
| Body style |
|
| Layout | 4x2 6x4 |
| Related | International S series "Schoolmaster"/International 3800 Powertrans T1250 |
| Powertrain | |
| Engine | Gasoline 197–236 hp (147–176 kW) Diesel 150–500 hp (110–370 kW) |
| Transmission | Manual Automatic |
| Chronology | |
| Predecessor | |
| Successor | |
The International S series is a range of trucks that was manufactured by International Harvester (later Navistar International) from 1977 to 2001. Introduced to consolidate the medium-duty IHC Loadstar and heavy-duty IHC Fleetstar into a single product range, the S series was slotted below the Transtar and Paystar Class 8 conventionals.
The IHC S series was produced in a number of variants for a wide variety of applications, including straight trucks, semitractors, vocational trucks, and severe-service trucks. Additionally, the S series was produced in other body configurations, including a four-door crew cab, cutaway cab, cowled chassis, and a stripped chassis (primarily for school buses). The chassis was produced with both gasoline and diesel powertrains (the latter exclusively after 1986), single or tandem rear axles, and two, four, or, six-wheel drive layouts.
The last complete product line designed within the existence of International Harvester, the S series was produced in its original form through 1989. During 1989, the S-Series underwent a major revision and was split into multiple model lines. After 2001, International phased in product lines based upon the "NGV" architecture; severe-service and bus chassis variants produced through 2003 and 2004, respectively.