belt is right is there ANYTHING inside the transaxle that could be installed wrong? it is the peerless typeI found the service manual. Page 72 has picture of belt routing. Get it while it is still there. I used M00175X to find it.
uni.edu/peterson/John%20Deere%20175%20Tractor/John%20Deere%20175%20Hydro%20Service%20Manual.pdf