You can try to tighten or loosen the screws abit. Too tight or too loose may cause leakage.
The may be also leakage at the diff. outer joint where the O-ring also leak. I f this the case, try to use O-ring from other brand.
I use Sakura S, see the diff. gear from Sakura for reference http://www.3racing.hk/manuals/SAK-S01%20Manual.jpg
I am fine, thank you. I finally purchase the Tamiya VDF for drifting.