i would probably change both just to have it done, but i have done this to have one start leaking too, so either way, change the leaking one, change the oil in both and go. but i changed mine at 30,000 on my xc, should have done it sooner
2012 Cross Country(Imp blue)
de-badged,(self tinted) Klockwerx flare, passenger backrest, passenger touring floorboards, VictoryHID kit, Miller Mufflers short baffles,Lloyds air filter(from witchdr.)Lloyds timing wheel(6*), adjustable drop link, cut seat, removed cats, PCV w/at.
1978(2009) Honda cb750 chopper