With the French on the left and an American armored division, the 5th, on the right, the XV Corps pushed north toward Argentan to close what became known as the Argentan-Falaise pocket, the maneuver to surround the Germans in Normandy. Ahead lay an upland forest, difficult terrain, and Haislip instructed his armored divisions to go around it, the French on the left, the Americans on the right. In a defiant or thoughtless, yet inexcusable, gesture of disobedience--perhaps because Leclerc had never before commanded a division in combat--Leclerc disregarded Haislip's order. He sent his elements around the left side, through the forest, and around the right. The latter troops preempted a major road reserved for the Americans and blocked their movement to Argentan, which was undefended. During the six hours it took Leclerc's men to complete the maneuver, the remnants of three panzer divisions arrived in Argentan and assumed defensive positions. They turned back the XV Corps and kept the Americans and French out of the town.

While with the 7th Armored the Group Headquarters operated in two echelons in different columns. On the 28th the echelon referred to as "Rear" became separated from the column it was following and advanced along a road that had not been cleared by the armor. In the village of Regault a German tank appeared which attacked this echelon of the Group Headquarters. The vehicles were quickly dispersed, a fifty caliber machine gun set up on a ground mount, a Bazooka team began firing, and a gun of the 558th was called on to go into position adjusted by a cub. The tank was driven off but it had take its toll. One man was killed, the battery commander, Captain Petty, and two men seriously wounded, and several other men injured slightly.