The "New Advanced Vehicle with Intelligence 5-speed" (NAVi5, also sometimes written "NAVI5" or "NAVI-5") was an automated manual transmission developed by Isuzu Motors Ltd. of Japan, and introduced in August 1984. It was initially developed for use in

trucks A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

, but was first made available in Isuzu's Aska sedan and subsequently the

Gemini Gemini may refer to: Space * Gemini (constellation), one of the constellations of the zodiac ** Gemini in Chinese astronomy * Project Gemini, the second U.S. crewed spaceflight program * Gemini Observatory, consisting of telescopes in the Norther ...

and their other Japanese domestic market vehicles. It preceded the likes of

Alfa Romeo Alfa Romeo Automobiles S.p.A. () is an Italian luxury car manufacturer and a subsidiary of Stellantis. The company was founded on 24 June 1910, in Milan, Italy. "Alfa" is an acronym of its founding name, "Anonima Lombarda Fabbrica Automobili." "A ...

’s ''

Selespeed Selespeed is the name of an automated manual transmission used in Alfa Romeo cars, developed by Italian company Magneti Marelli and made by Graziano Trasmissioni. The Selespeed is an automated manual gearbox with an electronic clutch. In its curre ...

'' and Opel’s '' Easytronic'' by more than a decade. It was superseded by the Smoother transmission in newer trucks.

Models

The NAVi5 was used in the following Isuzu vehicles: Isuzu added the NAVi6, a six-speed version, to the following trucks:

Features

Unlike "traditional" automatic gearboxes with a

torque converter A torque converter is a type of fluid coupling that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the torque converter connects the power ...

and

planetary gears An epicyclic gear train (also known as a planetary gearset) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates the planet and sun gea ...

, the mechanical aspects of the NAVi5 are identical to those of a conventional five-speed

manual transmission A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom, and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission system, where gear change ...

with a dry-clutch.240 Landmarks of Japanese Automotive Technology
/ref> The shifting and clutch operations though, are done automatically by two

hydraulic actuator A hydraulic cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment ( engineering vehicles) ...

s connected to an electronic computer (an 8-bit unit with 8 KB ROM and 192 KB RAM). The early version of the NAVi5 only had an automatic mode with an ability to lock out certain gears, thus operating in a manner similar to a traditional automatic. The later version added a manual mode, enabling the driver to select specific gears. The NAVi5 also came with autocruise and Hill-Start Aid as standard features. A Japanese television commercial for the Aska heralded NAVi5 as “Not a manual, not a torque converter.”

Reception

The customer reactions toward the NAVi5 were mixed. Some liked the more “direct” feel and better fuel economy it offered compared to those of typical automatic gearboxes. Others, however, were turned off by what they felt as awkward shifting program and the acceleration gap during shifting. The NAVi5 also required gentle throttle operations when accelerating from standstill since it didn't offer creep function. It was outsold by the conventional manual and automatic gearboxes in both the Aska and Gemini and subsequently dropped in the next generation Gemini. (Isuzu stopped manufacturing the Aska in-house after the first generation.)

References

{{Powertrain Isuzu Automotive technology tradenames Automobile transmissions Automotive transmission technologies