Moving data from 526X to RN3138

I am moving from a standalone 526X to a rack-mount 3138, both running 6.10.3 firmware and both in the same local network with gigabit connections.  I've found many ways for quickly transferring data among shares, but I haven't found a great way for moving data from the 526X to the 3138.  I'm looking at transferring 10 TB of data, so is there a way to perform the move (or copy) directly from the 526X to the 3138 through my network without involving a PC in the middle to slow the process down (I want to avoid 526X > PC > 3138)?