There, Wright's report of her engineering difficulties resulted in a survey of the ship. The inspectors recommended that a set of blowers be installed to increase the efficiency of her boilers. While this work was being performed by the repair ship Samson, it was discovered that the ship's port boilers were badly burned and required repairs. After temporary remedies were made, "Avenger" entered the Red River on 2 April carrying messages upstream. Two days later, she took station at the mouth of the Black River and, on the 7th, she entered the Ouachita River in an expedition commanded by Lt. Comdr. James P. Foster in the side-wheel ram Lafayette. The Union warships ascended that tributary as high as Ouachita City and confiscated some 3,000 bales of cotton; liberated 800 negroes; and burned the courthouse at Monroe, Louisiana, the railroad depot there, and a bridge over the stream. They stood down the Ouachita River on the 12th and returned to the Mississippi River when they learned that the famous Confederate cavalry commander, Major General Nathan Bedford Forrest, had attacked Fort Pillow, Tennessee. Foster, accompanied by "Avenger" and "Choctaw", ascended the Mississippi River to check Forrest. However, at Memphis he learned that, after pillaging Fort Pillow, the dreaded Southern raider had abandoned the fallen Union stronghold and retired inland. Therefore, "Avenger"—which had been suffering engine trouble—was free to remain at Memphis for repairs which lasted through the end of April. The ram then returned to the mouth of the Red River where she was assigned to guard the coaling barge stationed there. She was relieved by "Nymph" on 3 May and proceeded to the mouth of the Black River with additional coal barges in tow. There she was again relieved and steamed upriver to join "Forest Rose" on patrol in the vicinity of Fort deRussy. At that fort, "Avenger" exchanged shots with Southern sharpshooters on 12 May; and she and her consort engaged the enemy several times as they continued patrols up and down the river during the next five days. The ram returned to the mouth of the Red River on 17 May to coal and then continued downriver to Simmesport, Louisiana, to embark Major General Nathaniel P. Banks, the commander of the Army forces involved in the Red River expedition, for passage to New Orleans, Louisiana. The advance of his troops had been checked at the Battle of Pleasant Hill and a shortage of ammunition, supplies, and water had forced him to withdraw.