Son was driving down the highway, something went bang and engine died. With clutch in, engine will start and run. Let out clutch in any gear and engine dies. Let out clutch in neutral, it runs. I'm assuming transmission is broken. How hard of a fix. Only replacement we can find is a rebuilt for $750. Truck isn't worth that to fix. Anybody know what usually breaks? cluster gear? synchros? input shaft? I've got experience on older manuals, mostly the old Muncies and Ford top loaders and feel comfortable I can rebuild this, but would like some idea of what I'm up against before I tear it apart. Thanx...