Just looking around on ebay and found this under Himoto.I know someone was looking for these. A hell of alot cheaper than buying them both and the gears look different.
http://cgi.ebay.com/050109-Center-Diff-Mount-1-5-rc-part-HPS-Himoto-Redcat-/140405188249?cmd=ViewItem&pt=Radio_Control_Parts_Accessories&hash=item20b0cd2699
http://cgi.ebay.com/050109-Center-Diff-Mount-1-5-rc-part-HPS-Himoto-Redcat-/140405188249?cmd=ViewItem&pt=Radio_Control_Parts_Accessories&hash=item20b0cd2699