Increased issues with filament grinding
I've encountered this on my Replicator Dual in the past. I was only using MakerBot branded ABS filament, so it wasn't a quality issue for me.

What I found was that the delrin plunger design that "helps" keep the filament in contact with the drive gear wasn't actually helping. So, I installed the newer assemblies that use a spinning bearing to contact with the filament.


Install (or keep installed) a spring loaded extruder assembly.
When feeding filament, loosen the spring and gradually tighten until the filament begins feeding on its own.
Try to stay close to the recommended print temperatures for the material. ABS is typically somewhere around 225C, but it depends on the supplier.
Ensure your filament is stored in a dry place. This is way more of an issue for PLA, but it doesn't hurt to keep your material protected.
If it continues, perhaps swap out the drive gear itself. If you've dropped your motor or somehow a burr has developed on any of the teeth, naturally the burr will cut away the material. Gears are very temperamental and should be considered a consumable.