1998 craftsman 19.5 turbo cooled won’t go forward or reverse

Please help my mower will not move, it’s a 1998 craftsmen 42in. It stays in neutral. I have done some checking and it has both keys in the drive tires. However, after removing the back plate and looking over the drive belt is good the only thing i noticed is there is a rod on the right side that when pushed the wheels move. I did some further digging and on the shifter there is a spring that is freely there and I assume it’s the issue except I cannot seem to find where it belongs?