I have a 7173H hydro tractor with a 48"deck. The drive belt broke and I can't find a replacement. I have a number for the belt 039179 which has a new number of 07211100. There is a note in the owners manual from the previous owner saying it takes 2 of these belts (matched pair) I removed the broken belt and it is a single belt. The 07211100 belt is 34" long. The belt I took off is much longer and it's a single belt. Does anyone know the correct belt for this deck.