Hi Len!  I ran it slowly and watched both shafts and they were turning ok so they are still connected. I ran it up again and, like I said, it runs smoothly but slow and after a few feet it abruptly stops, shorts out the system for 3/4 seconds, then powers up, lurches about a foot or so stops and repeats the whole action over and over until I shut down the DCC system. 
A real puzzler!

Bill

I will take a look as I still have the shell off.  Be right back!

I just received a warranty replacement RS3 and put it on the layout to test it out.  When applying the throttle it will lurch forward about a foot, short out the DCC system, reboot, lurch forward another foot or so and repeat the same issue.  I do not have issues with any of my track or other locos and it is definitely shorting out as all my sound locos go silent for about 5 seconds while the RS3 gathers itself up to come back to life and run another foot.  This repeats again even after setting CV8 to 8 to reset the module.
I am hesitant to tell Service that I am having a problem with this one as it took a bit to get the first one looked at and exchanged.  Different issues with that one, no lights and extreme motor noise when it did run.
I checked the power pick-ups on the wheels and they all seem to be OK, making good contact. I used another Bachmann module and got the same issues.  I am suspecting that the motor has an issue but if either the Bach Mann give me some ideas or should I just contact the Service Department?