Starter spinning no start

I have been having a problem with my ram. I turn the key and the starter activates and spins but no starrt. It started as once in a while but within a month of use has become a problem to where the only way to start is to try key couple of times then it catches and starts. pulled the starter off and no metal shaving were present to indicate flywheel damage. Went and had the starter rebuilt with new clutch and bearings and general rebuild. No fix. still having same problem cannot figure it out. Everything up to the starter works because it is spinning and the gear is coming out like it should but it doesnt start the truck when it catche`s the flywheel it starts without a problem. the sound it makes when the starter turns is like the sound when you turn the key with it running. any help would be appreciated