The bastard product of the cavalry's desire for an "armored jeep" that wasn't just an M113 APC, the M114 was, not to be excessively cruel, a piece of shit. Built largely from off-the-shelf components by Cadillac, the M114 became notorious in the armored cavalry for its poor off-road mobility, tendency to get stuck in ditches due to its nose overhanging its tracks, and (despite the use of a bog standard GM power train based on the Chevy 283 V8) mechanical unreliability. When the M114 was deployed to Vietnam, armored cavalry units discovered that the M114 was also horribly vulnerable to mines: a mine that did serious (but repairable) damage to an M113 would literally blow an M114 in half.
As if all this wasn't enough, the original M2HB machine gun armament was replaced in later examples of the M114 with a Hispano-Suiza 20mm cannon, a weapon that proved too much for the lightweight recon vehicle's chassis and for most of the turret mechanics working on the vehicle. The already poor off-road performance got worse with the additional weight of the cannon and its ammunition. By November of 1964 the M114 was withdrawn from American and ARVN units in Vietnam and replaced with the M113 ACAV, an improved version of the M113 APC with more guns and armor. Instead of being scrapped, however, the withdrawn M114s were sent to other cavalry units in Korea, the United States, and Germany where they continued to fail at their assigned tasks until put out of their misery by Chief of Staff Creighton Abrams (a former armor officer) in 1973.