JD 310c Transaxle won't pull

I have A JD 310c 2wd. Last fall it stopped pulling. just like it is in neutral. no warning, no odd noises. The drive line going from shuttle tranny to the 4 speed transaxle is turning, but no matter what gear it is in the wheels will not pull. off the ground i can turn them by hand. It is spring now, so I need to get this thing running. Is there A common problem with these transaxle, or can someone tell me where to start. Thanks Ken

JD 310c Transaxle won't pull