The International 9000 Series is a range of trucks that was manufactured by Navistar International (previously International Harvester). Introduced as the Transtar 4000 in 1971, the model line was produced across three generations until 2017; following the incorporation of Navistar, the Transtar was rebranded as the 9000 series. Slotted below the Paystar range (in terms of size), the 9000 series was a conventional-cab truck configured primarily for highway applications. Produced exclusively in a Class 8 configuration, the Transtar 4000/9000 Series was offered in multiple layouts, including single or tandem rear axles, daycabs or multiple sizes of sleeper cabs. During the 2000s, International phased out much of the model line in favor of the newer ProStar and LoneStar; after a 46-year production run, the final 9900i was produced in 2017. First generation (Transtar; 1971-1985) For 1971, International introduced the Transtar 4200/4300 series as its heavy-duty conventional. Replacing the Transtar 400 (an update of the D-400 introduced in 1961), the 1971 Transtar introduced an all-new cab, replacing the "Emeryville" cab (introduced in 1957). The Transtar was offered in two model lines, the standard-hood 4270 and the long-hood 4370. The cab of the first-generation Transtar was adopted for the severe-service Paystar 5000; its doors were shared by the 9000-series COEs. A steel cab was standard; an aluminum cab was optional. At its launch, the Transtar 4200/4300 was offered with a range of diesel engines, with the 4200 offered with V8 engines and inline-engines for the longer-hood 4300. A Detroit Diesel 260 hp 8V71 V8 was standard on the 4270, with a 230 hp Cummins NH inline-6 standard on the 4370; the latter model was offered with a 434 hp Detroit Diesel 12V71 V12. The engines were paired with manual transmissions, ranging from 5 to 16 speeds (along with optional 4-speed auxiliary transmission). At the end of the 1970s, the 4300 was fitted with the largest diesel engines ever fitted in a road-going vehicle, including the 450 hp Cummins KT inline-6 (1150 cubic inches) and the Caterpillar 3408 V8 (1099 cubic inches). Second generation (1985-1999) Following the corporate transition of International Harvester to Navistar, the Transtar series underwent several minor revisions to the exterior and badging, with the model line becoming the International 9370. The 4270 was dropped, with the 9370 receiving a larger grille and hood (distinguished by vertically-stacked headlamps). In 1989, Navistar introduced several changes to the model line; in line with