After end of the war, in October 1920, Grechkin became assistant commander of the 37th Separate Rifle Brigade (later the 37th Rifle Division) in the North Caucasus Military District. He later became commander of the 111th Rifle Regiment and in June 1922 transferred to become assistant commander of the 13th Rifle Division's 37th Rifle Regiment, in the same district. In July 1923, Grechkin took command of the Rostov Separate Guard Battalion. He became assistant commander and acting commander of the 22nd Rifle Division's 64th Rifle Regiment in June 1924. After graduating from the Vystrel commander improvement courses in 1926, he was sent to the Central Asian Military District and appointed commander of the 3rd Turkestan Rifle Division's 9th Turkestan Rifle Regiment. Between April and July 1931, he led the regiment in battles with Ibrahim Bek, the leader of the Muslim Basmachi insurgent movement. In January 1932, he was transferred to become assistant commander of the 15th Rifle Division and in July 1935 became acting division commander. On 26 November, when the Red Army reintroduced regular military ranks, Grechkin became a kombrig.