The Hummer is not the Army's first attempt to retire the aging jeep.

"They started thinking about replacing the jeep in 1940," Capt. Edwin J. Messinger said. "If you go out and look at what it's carrying, it's overloaded in almost every case."

Hummer's ancestors included the XR311, later dubbed the Combat Support Vehicle. It was canceled. Then came the Expanded Mobility Tactical Truck (EMTT) and the High Mobility Weapons Carrier (HMWC). Those were canceled, too.

Hummer was conceived in January 1979 in a document called a Joint Mission Element Need Statement, or JMENS, which proposed melding elements of the deceased EMTT and equally deceased HMWC. In its current incarnation, Hummer comes in 15 models and its uses range from an ambulance to a platform for antitank missiles.

Originally, the Army planned to take seven years developing Hummer. In an attempt to get it into the field faster, that was compressed into five years and the testing period for Hummer was squeezed from 14 months to five.

That testing was arduous but perhaps less grueling than the bad press the Army faced when accounts of the Hummer's shortcomings became public. The vehicle was cursed with clogged radiators, dirt and water in the engine, leaky fuel systems, axle problems, tire problems and so on.

Today, even the General Accounting Office, a harsh critic during Hummer's gestation, agrees that most problems have been fixed. Not all kinks have been ironed out, however. Hummer drivers are instructed to swivel the vehicle's gun turret five times to the left, then five times to the right every morning, to shake loose the dried mud.

A special device in Hummer's wheels, designed to allow the vehicle to "limp back" home even with four flats, has shown an annoying tendency to shred the tires. Also, Hummer grew so heavy that under some conditions a helicopter cannot simultaneously lift its crew and equipment.

Hummer's current program manager, Col. Joseph A. Petrolino Jr., has been on the job only 10 months, underscoring the frequent turnover of key executives that has plagued the military for years. The average tenure for program managers on major Army weapons is 2 1/2 years, which an Army spokesman acknowledged may affect the program "in a nonoptimum manner."

"Since it takes a manager at least a year to master the ins and outs of a complex project, it's hard to escape the conclusion that these weapon programs are being managed at least half the time by people who don't really know what they are doing," Sen. William V. Roth Jr. (R-Del.) said last year.

An internal Air Force memo in September 1983 observed, "It's like sending a lamb to slaughter."

That issue is of little concern to Hummer's maker, AM General, which is so pleased with the vehicle that it is contemplating a civilian model for well-to-do sportsmen.

"When this Hummer gets out in the field and really begins to hum, it will become one of the most prized pieces of mobile equipment in the history of the U.S. Army," AM General President Lawrence Hyde has said. "The old jeeps, like some of the great horses of the Civil War, will be forgotten by the generals and their historians once this one begins to climb over peaks and valleys, troughs and through impenetrable thickets."