There is a countershaft in the bottom below the main shaft,if the trans had water in it ,there is a strong possiblity that the bearings could be rusted up and siezed. If you were to get it freed up and turning,i wouldnt use it. Id take it apart and replace bearings and whet ever else it neede. If you cant get it to turn at all, tear it apart and see what whats going on in there.
