Distributor Problem

My engine dead on my Ply. Voyager 2.5 liter. I believe I have located the problem. I can turn the distributor rotor 360 degrees by hand so I pulled the distibutor and it is fine. It appears that the gear in the engine where the dist. installs in is broke. I check timing belt and all is good. when I crank engine all three gears turn. Has anyone had same type of problem and can it be fixed without pulling engine.