For many city businesses and regional haulers, older versions of the standard Class 8 trucks were not a great option. Sure, they had heavy-duty power and capacity but the fuel economy was low and the maneuverability was limited. For these reasons many delivery companies, construction trades, and waste haulers chose to go in a different direction. 

Fortunately, Kenworth started releasing Class 7 trucks in 1988 that can easily be modified to light Class 8 units when needed to ensure high productivity with acceptable operational costs. One of the most famous models is the Kenworth T400. 

This article will look at the unit’s history, development, and overall design to see why the T400 has been a go-to truck for many businesses through the years.

History of the Kenworth T400

Like other Kenworth trucks, the T400 had a long history of development. Here’s how the T400 that we know today was developed.

Kenworth T600

The Kenworth T400 was based on the design of the 1984 Kenworth T600, which was a Class 8 truck. 

While other semi-tractors were primarily designed for high payload capacity and powerful riding performance, the T600 was built to attain excellent fuel efficiency through aerodynamics. 


Pioneer in aerodynamics - Kenworth T600

The T600 came with a set-back steer axle, a sloped hood line, a smaller turning radius, and longer front springs. These features create better suspension and improved weight distribution. Aside from improving maneuverability, these specifications also boosted the model’s aerodynamics by 50%. The design was tested for fuel efficiency, and the T600 came out 20% more fuel efficient than the popular Kenworth W900 model.

Dubbed the “Anteater” due to its looks, the T600 contributed to approximately 40% of Kenworth’s sales in 1985. Thanks to its innovative aerodynamics, the T600 also inspired numerous newer models. 

Kenworth T400

Kenworth began exploring the possibility of repackaging the T600 design for various hauling and business applications. In 1988, the company released the T400, a Class 7 and 8 commercial truck version of the T600 semi-tractor.


The powerful Class 8 Kenworth T400

The T400 came with a slightly shortened hood of 112-inch BBC length. It was initially designed as a single-axle day cab, a tandem axle sleeper, and even a standard dump truck. Its straightforward design made it famous among regional shipping and local delivery services. 

Despite its popularity, Kenworth ceased production of the original T400 in 1997. However, upgraded and modified versions of the model were released the following year.

Kenworth T450

In 1998, Kenworth released the T450, a light-duty version of the T400. Despite being a slightly sized-down version, the T450 still provided good payload potential for users.


The economical Kenworth T450

The T450 was dubbed the most economical-to-own Class 8 medium conventional cab truck. It was made with a 112-inch BBC dull truck with a set-back front axle and a GVW of 62,000 lbs. The truck offered great forward weight transfer and a tight turning circle, making it perfect for dump, lowboy, bulk tanker, flatbed, mixer, and other similar applications. It also sported 8.3- and 19-liter engines. 

In terms of its exterior, the T450 came with a sloped hood, 17″ x 36″ rear windows, peeper windows, and cab-mounted mirrors. The model also gave drivers smooth rides with 64-inch-long front springs.

Kenworth T440

In 2009, Kenworth released the T440, categorized as a Class 7 vehicle and a light Class 8. Some of its unique features included a multiplexed dash, Kenworth Driver Information Center, and extended day cab configurations for all-day operations.


The reliable Kenworth T440

Like the T400, the T440 was initially designed to address the growing demand for delivery trucks. It was built to suit regional hauling, city pickup services, and other vocational duties. Despite its popularity among city businesses, Kenworth ceased production of the T440 in 2021.

Kenworth T470

In 2009, Kenworth announced that they would release the T470, an upgraded version of the T400. The T470 was first made with a Cummins ISL 9-liter engine, but in later years, Kenworth also made the model with other engine choices. 


The upgraded Kenworth T470

While the T470 had a great following among local business owners, its sales didn’t skyrocket, mainly because of its excessive similarity with the T440. The T440 units worked as extended cabs and small sleepers, while the T470 units only came in day cabs. The model was also discontinued in 2021.

Kenworth T480

Released in 2021, the Kenworth T480 is now the latest offering in the T4 line. The T480 was released as a Class 8 commercial truck with a standard PACCAR TX-8 automatic transmission. It’s made available with multiple engine options, such as the PACCAR PX7, PACCAR PX9, and the Cummins L9N Natural Gas. 


The all-new Kenworth T480

The T480 continued the T4 tradition of having sloped hoods for better aerodynamics.

Design of the Kenworth T400

The overall design of the Kenworth T400 was based on the premise that sometimes excellent fuel economy doesn’t come at the expense of reliability, longevity, serviceability, driver comfort, and residual value. Kenworth wanted to provide the greatest value for business owners by releasing the first short pay-back medium conventional cab built for the long haul.


Old but still gold - the 1990 Kenworth T400

To do this, Kenworth equipped the T400 with the following features:

  • Advanced aerodynamics for fuel savings;
  • Set-back axle for maximum payload;
  • A custom frame of 110,000 PSI yield strength for additional foundation;
  • Lightweight, corrosion-proof cab with a three-point cab mounting system to increase cab life;
  • Corrosion-resistant battery box environment for increased reliability;
  • UNITGLAS hood and fender assembly, protecting the engine as it sits high in the frame outside the cab for complete access; and
  • Better cooling system with straight sections of reinforced rubber hose for easy replacement.

These specifications show that Kenworth took the necessary time creating the best-value medium-duty truck with the T400. Aside from all these features, the T400 was also designed to ensure driver comfort with an optimized size of the rear windows, an AirCushion seat, accessible switches and controls, low and pull-type door handles, and bulkhead-type doors.

With its overall design, Kenworth fulfilled its promise of maintaining a high residual value for the T400. It’s no surprise that the modern models of the T4 line are still in high demand.

Making the Kenworth T400 Business-Ready

Kenworth loaded the T400 with impressive specifications to ensure it could provide an optimal riding experience for the long haul. For this reason, the only upgrade that most business owners and truck drivers do to their T400 units is to improve their HVAC boxes.


Upgraded HVAC units for the Kenworth W900, T800, T600, T400

Like any commercial vehicle, continuous use and age diminish the efficiency of the T400’s HVAC box. Fortunately, premium truck parts providers offer high-quality plug-and-play T400 HVAC boxes

When looking for an HVAC box replacement for your T400, go for boxes that are spot welded and built with 18 gauge 304 stainless steel. These heater boxes are considered the most durable and reliable units that can withstand all-day use.

Enjoy the Power and Profitability of the Kenworth T400

Kenworth made one powerful truck with the T400. Stay on top of your routine maintenance and your decades-old T400 will give you the productivity and profitability you need for your business.

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