For F free of rank 4, a generating set for Aut (F/[F′, F′, F′]) exhibiting countably many wild automorphisms is obtained. Also included are examples of wild automorphisms in Aut (F/Vk+1) which are tame in Aut (F/Vk) for k ≥ 1, where Vk = [F″, F,…, F] (F repeats k times).