Employee was installing a transmission. Laying on his back & pushing against the transmission with his feet, he felt a pain through his leg to his toes. He reported his injury on 6/23/06 but declined medical treatment. EE aggravated his back last week, 10/5/06, while working in a cramped & awkward position causing his pain to flare up & on 10/9/06 he asked to seek medical help.