cat d7e generator belt

I am working on a Cat D7e 48a dozer . The generator belt broke and I got one from the cat dealer # 5m-8135 . The problem is I can't get it over the fan . I have tried every which way , inside out but to no success . I called the dealer up and double checked on the part and they say it is right. But it is short , unless you have to take the fan off ( which looks like a monster job) . anyway the belt is 1/2 x 51.5" long . any thoughts? Thanks