Slash 4x4 differential leak

[Raidem81]

Hello everyone,
i have a slash 4x4 since 3 years and i'm very happy but i have a little problem on my diffs, all the time i re-oil for the first 3 packs they start to leak the silicon oil from inside, i try several time to rebuild installing new rebuild kit with new o-rings (the blue one) new gasket and new diff case.....i pay attention to everything, cleaning properly and rebuilding without mistakes.....it is a common problem of this kind of diffs or what???????
Hope somebody can help me
Thanks a lot

[rcrexing]

i havent heard of this happening before but you might want to check your bearings again and the casing screws somtimes screws can be loose and have some extra room to move