Output Shaft C-Clip

[punxva]

Ok so I've searched all day for this...

When i swapped my ring gears on my diff awhile ago i noticed my drivers side output shaft didn't have a c-clip on it, and that made is not stay into the diff, well my friend said it'll be fine since the axle will hold it in place so we installed it, now after about 2 months, I've noticed my diff doesn't really lock that well, on uneven surfaces like going out of parking lots the wheels feel like they aren't both catching, and I've noticed some gear oil in the driveway after driving...

Where can i get this clip and do you think thats what is causing all of these problems, well at least the leaking part which is causing the rest of them...