after 2 year down is 3rd yr down allowed in engg courses of pune uni... to get eligible for 5th sem..?

after 2 year down is 3rd yr down allowed in engg courses of pune uni. to get eligible for 5th sem.? In pune un how many year downs are permitted according to pune university? I sought adm to direct 2nd yr degree courses in E&TC after diploma... but is 3rd yd allowd I have failed in 2nd yr 2 time