From August 1937 the 75 gun tanks of the second and third series were taken into production. The first five of these were only delivered between 3 and 5 May 1938, the next ten between 2 and 3 June. On 27 July 56 had been produced and 34 delivered. The penultimate delivery was on 21 November, the last vehicles were probably produced just before the end of 1938. The second and third batch incorporated the improvements made in 1937 on the first batch but also featured some unique modifications such as a Synchromesh gear box and reinforced chassis girders in the front of the vehicle to ensure a sufficient frame rigidity: a severe distortion had occurred on the earlier vehicles.