	In April 1922, Grebennik became an instructor with the 455th Rogozhsko-Simonovsky Regiment of the 51st Rifle Division. He transferred to the border troops of the OGPU in October 1922 as a commissar of the Ochakovo Border battalion. Grebennik graduated from the Graduate School of the USSR Border Troops in 1924. In September, he became a platoon commander of the Odessa School of border troops regiment. He became the head of border troops at the Polish border and the motorized group of the Moldovan border detachment. In November 1929, he became the assistant chief of the drill for the 21st Yampolsky Border Detachment. Grebennik was appointed commander of the 5th Mechanized Regiment of the Order of Lenin Separate Mechanized Division of special purpose troops in December 1931. In July 1935, he graduated from the courses at the Military Academy of Mechanization and Motorization of the Red Army. Grebennik was promoted to colonel in April 1936.