The new tank was to be equipped with a number of advanced features such as newly developed "kneeling" hydropneumatic suspension and housing the entire crew in the large turret, and was armed with a 152mm XM150 gun/launcher, which could use both conventional ammunition and the MGM-51 Shillelagh missile for long range combat.

[3] The program faced significant challenges from the start, including poor communication and coordination between the American and West German teams working on the project.

After serving in the US Army Air Forces during World War II, McNamara became a "Whiz Kid" at Ford Motor Company, where he later rose to become president.

He had shepherded development of the abortive Ford Cardinal – a cancelled project involving the redevelopment for US and other international markets of a compact family car designed by engineers in both the US and Germany.

[4][page range too broad] As Defense Secretary, McNamara began to apply his methods of industrial management to military production.

While West Germany used American M48 Pattons, it had historically excelled in engineering armored fighting vehicles and was known to be proceeding with plans to design, develop and build its own tanks.

In 1961, McNamara approached German Minister of Defence Franz Josef Strauss about beginning a collaborative main battle tank program.

McNamara continued to press for Germany's cooperation in a common tank program, succeeding the next year in brokering a tentative agreement with the Germans.

Consequently, McNamara's seven-year timeline to production was opposed by senior armor officers, who believed an all-new MBT was more urgently needed.

Within US armored circles, it was believed that there would be a net technology transfer towards Germany and there was a common belief that the UK would make a better partner.

Dolvin chose GM, anticipating the company would bring more fresh ideas to the table than longtime incumbent tank producer Chrysler.

[4] There were disputes over almost every part of the design: the gun, the engine, and the use of both metric and SAE units in the separately manufactured components of the tank.

The disagreement rose to McNamara and German Defense Minister Kai-Uwe von Hassel, who were also unable to settle on a common measurement system.

[8] Many Americans both inside and outside the project, including General Creighton Abrams, hoped for an amicable end to German involvement in the program.

Luczak found support from Deputy Secretary David Packard, who brokered an agreement to end the tank partnership in January 1970.

They were armed with the M68 105 mm rifled gun (developed from the British 105mm L7) and designed to counter Soviet T-54/55 tanks, which they successfully did, according to Israeli combat experience.

But it became very clear that due to the same experience the next generation of Soviet tanks would have increased firepower and protection, and both designs would be placed at a disadvantage by the new smoothbore gun in the T-62.

The vehicle used an advanced hydropneumatic suspension system that allowed for fast cross-country speeds even though it was to weigh 45 tonnes (50 short tons).

[12] Although the auto-loader was supposed to be capable of loading both missiles and combustible-case tank rounds,[12] the German Rheinmetal autoloader was prone to deforming the ammunition's fragile combustible cases.

The automatic loading system had a vertical rotating magazine equipped with 16 containers, for 5 types of ammunition, which allowed a firing speed of 12 rounds per minute.

[3] The secondary armament of the MBT-70 consisted of a remote-controlled 20 mm Rh 202 autocannon (with storage for 750 or 660 rounds) for use against aircraft and light armored vehicles.

[17][1] The gun could be retracted into a container behind the driver's rotating cupola for protection as well as to reduce overall height, and was operated remotely by the commander.

It was heat treated to 500 BHN, like the other types of high hardness armor, but it was produced from the start in the form of plates 40 mm thick.

One solution proposed removing radiation hardening from the turret, but this called into question the wisdom of the driver-in-turret configuration, which was intended to protect the crew in the event of a nuclear blast.

[25] A July 1969 House Armed Services subcommittee report on the troubled M551 Sheridan asked that funding for the MBT-70 be withheld pending a comprehensive review of the program.

[26] In August 1969, Senator Thomas Eagleton was granted a request that the Government Accounting Office undertake an audit of the program.

Acting on this recommendation, Deputy Secretary of Defense David Packard agreed to withhold $25 million earmarked for the production of six prototypes while the DoD completed a review of the project.

[32] Work began on converting the existing MBT-70 design into a low-cost "austere" alternative that would use only American-made components, resulting in the visually similar XM803 prototype.

Luczak claimed General Motors charged a premium for its defense contract work, which it considered insignificant compared to its burgeoning automotive business.

[4] In the 1989 book King of the Killing Zone author Orr Kelly called the end of the MBT-70 program, "one of the most fortunate occurrences to befall the U.S.