The Soviet corps equipped with these new tanks lost most of them within weeks. The combat statistics for 1941 show that the Soviets lost an average of over seven tanks for every German tank lost.
The Soviets lost a total of 20,500 tanks in 1941 (approximately 2,300 of them T-34s, as well as over 900 heavy tanks, mostly KVs). The destruction of the Soviet tank force was accomplished not only by the glaring disparity in the tactical and operational skills of the opponents but also by the mechanical defects that affected the Soviet armour pool. Besides the poor state of older tanks, the new T-34s and KVs suffered from initial mechanical and design problems, particularly with regard to clutches and transmissions. Mechanical breakdowns accounted for at least 50 percent of the tank losses in the summer fighting, and recovery or repair equipment was not to be found.The shortage of repair equipment and recovery vehicles led the early T-34 crews to enter combat carrying a spare transmission on the engine deck.
Other key factors diminishing the initial impact of T-34s on the battlefield were the poor state of leadership, tank tactics, initial lack of radios in tanks, and crew training; these factors were partially consequences of Stalin's purges of the Soviet officer corps in 1937, reducing the army's efficiency and morale. This was aggravated as the campaign progressed by the loss of many of the properly trained personnel during the Red Army's disastrous defeats early in the invasion.