Trouble printing spare Prusa Gears

I have tried 3 times now to print the small gear for my Prusa and failed.
Other prints come out great, the only very minor issues here and there (other than I keep breaking of slipping filament) :(

The gears will come out nice on one side, and the other will have odd shapes to the teeth.
I have tried it with and without the cooling fan. Last time the side the fan is on turned out nice, but that might have been by chance.

Last print was these settings.
ABS
230C
90C
Layers= 0.18
Walls= 0.8
Fill= 100
Print Speed= 65

http://jtice.smugmug.com/3D-Printing...6_221855-L.jpg

Given the ripple in the walls, it looks like your belts are a bit loose.

It looks like the head is dragging filament back with it on one side of the print, deforming the teeth. Have you calibrated e-steps per mm on your printer? If the printer is extruding less than it thinks it is, it could be dragging back. I would also look at infill (too low and it may be collapsing) and acceleration (too high and it may have the drag back effect).

230 is probably the upper end of ABS - maybe trying lowering the temperature by 5 degrees.