The International 3900 was a front-engine Type D bus chassis manufactured by Navistar International

Navistar International

Navistar International Corporation is a United States-based holding company that owns the manufacturer of International brand commercial trucks, MaxxForce brand diesel engines, IC Bus school and commercial buses, Workhorse brand chassis for motor homes and step vans, and is a private label...

, used for school bus

School bus

A school bus is a type of bus designed and manufactured for student transport: carrying children and teenagers to and from school and school events...

 applications. It was the replacement for the 1853-FC chassis, based on the S-Series "Schoolmaster"

International Harvester S-Series (bus chassis)

The International S-Series "Schoolmaster" was a Type C bus chassis manufactured by International Harvester, which became Navistar during its production run. It was introduced in 1979 as the replacement for the Loadstar bus chassis; it was used for both school bus and commercial bus applications...

 introduced in the late 1970s. Introduced in 1990, the 3900 was produced until 2010.

Availability

Early in its production life, the 3900 was widely used in the school bus industry by body manufacturers as a replacement for the General Motors S7 and the Asia Smith chassis. In 1993, both Carpenter and Wayne Wheeled Vehicles both switched chassis suppliers, leaving AmTran and Canadian manufacturer Corbeil as the sole users of the 3900; Corbeil switched to a rear-engine design before abandoning production of Type D buses for good in 2000. Corbeil's transit-style buses (nor any of their other full-size offerings) were never sold in the United States.

The final bus model that used the 3900 chassis was the FE300 from IC Bus, which was an evolution of the Ward Senator from 1990. In 2010, IC discontinued production of the FE with no replacement currently announced. They continue to offer Type B, Type C, and rear-engined Type D buses.

Buses produced on the 3900 include:

Manufacturer	Model Name	Production Years	Notes
American Transportation Corporation (AmTran) AmTran American Transportation Corporation was a builder of school buses in the United States. Founded in 1980, the company traces its roots back to Ward Body Works, which was established in 1933. AmTran was acquired by Navistar International in 1994-1995, a move that would begin a series of alignment...	Genesis FE	1992-1997 1998-2002	The AmTran Genesis and AmTran FE are evolutions of the Ward Senator.
Carpenter Industries, Inc. Carpenter Body Company Carpenter Body Company, also known over the years as the Ralph H. Carpenter Body Company, Carpenter Body Works, Inc., Carpenter Manufacturing Company, Carpenter Industries, Inc., and Crown By Carpenter, was a bus body manufacturer based in Mitchell, Indiana, United States...	Counselor FE	1991–1992	In 1993, Carpenter switched to a chassis from Spartan Motors Spartan Motors Spartan Motors, Inc. is an engineering firm and manufacturer of custom-designed motor vehicle chassis and bodies. The company is based in Charlotte, Michigan with 870 employees and a net profit margin of 2.42% . It was started in 1976 by Charles Robert McManamey and a group of individuals whose...
Les Enterprises Michel Corbeil, Inc. Corbeil Buses Corbeil Bus Corporation is a school and commercial bus manufacturer, based in Hutchinson, Kansas. It was created from the acquisition of predecessor Les Enterprises Michel Corbeil by Collins Industries in 2007...	EMC 1st Premier	1991-1999	The 1st Premier was never sold outside of Canada.
IC Bus	IC FE300	2003–2010	IC Bus was the final user of the 3900 in school bus form.
Ward School Bus Manufacturing, Inc.	Senator	1990–1992	The Ward Senator was the first bus to use the 3900 chassis.
Wayne Corporation Wayne Corporation Wayne Corporation was a large manufacturer of buses and other vehicles branded with the trade name "Wayne." The corporate headquarters were in Richmond, Indiana, in Wayne County, Indiana, in the United States...	Lifestar Wayne Lifestar The Wayne Lifestar is a front-engine transit-style school bus produced by Wayne Corporation and its successor Wayne Wheeled Vehicles. It was introduced in 1986 and production continued until the demise of Wayne Wheeled Vehicles in 1995.-Overview:...	1991–1992	In 1993, Wayne Wheeled Vehicles restarted production of the Lifestar with a chassis from Crane Carrier Corporation Crane Carrier Corporation Crane Carrier Company is a manufacturer that specializes in construction truck and garbage truck chassis. Located in Tulsa, Oklahoma, it was established by Samuel Zeligson in 1946, along with the affiliated Zeligson Trucks. The primary design of CCC's trucks are Cab-Beside-Engine or half-cabs,... .

Powertrain

Much like its predecessor borrowed its powertrain and suspension components from the S-Series "Schoolmaster"

International Harvester S-Series (bus chassis)

The International S-Series "Schoolmaster" was a Type C bus chassis manufactured by International Harvester, which became Navistar during its production run. It was introduced in 1979 as the replacement for the Loadstar bus chassis; it was used for both school bus and commercial bus applications...

, the 3900 was mechanically related to the 3800

International 3800

The International 3800 is a Type C bus chassis that was manufactured by Navistar International for school bus and commercial bus applications. It was produced from 1989 until 2004. The replacement for the S-Series "Schoolmaster", the 3800 used powertrains and components from the 4700 and 4900...

 (which was a cowl-chassis version of the International 4700/4900.

Engines

The International 3900 was only produced with diesel-fueled engines throughout its production life. All of them were sourced from Navistar International. Unlike the rear-engined 3000

International 3000

The International 3000 is a rear-engine Type D bus chassis manufactured by Navistar International, used for school bus and commercial bus applications. It was introduced in 1996 as the chassis for the then-new AmTran RE. The 3000 is used primarily for school buses and only by IC Bus...

, only 6-cylinder engines (all from the DT engine family

Navistar DT engine

The Navistar DT engine family is a line of mid-range inline-6 diesel engines. Withhorsepower ratings ranging from to , the Navistar DT engines are used primarily in medium-duty truck and bus...

) were used.

• DT360A (1990–1994)
• DT466E (1990–2007)
• MaxxForce DT (2008–2010)

Transmissions

Unlike the 3800 conventional, the International 3900 was only produced with automatic transmissions.

• Allison
  Allison Transmission
  Allison Transmission is an American manufacturer of commercial duty automatic transmissions and hybrid propulsion systems. Allison products are specified by over 250 of the world’s leading vehicle manufacturers and are used in many market sectors including bus, refuse, fire, construction,...
  
  AT545
• Allison MT643
• Allison World Transmission (MD3060)