These are wear marks on my ats 4.9 final drive where the ring gear contacts the countershaft. Is this still considered usable or is it damaged beyond use?

 

Time for a replacement.

I've replaced ATS and SRR gear sets because the pinions that have done that.

 

Replacement for sure, the teeth have either sunk too far into the root of the gear and caused permanent damage to it, or excessive power has caused permanent moving of the tooth itself. The wear does look uniform, which would suggest the pair was too closely spaced to begin with, but I see no wear on the top of the tooth to indicate interference. This must simply be overload or inferior materials. I would doubt any repositioning would have changed the outcome, only the location of the stress.

Please specify your power and usage so others may reference this picture in the future. Also is the damage concentric? Does it vary in any given gear tooth, etc.

 

SRR pinion that was replaced with a Gear-X FD....

 

Replace it. I've replaced a lot of broken ATS FD's.