ReadyNas Duo v1 expansion

Have a ready nas duo v1 4.1.10 with 2 drives, one 2tb and 1 1tb. I'll be replacing the 1tb drive with a 2tb drive and as I understand the data will automatically sync up between the new 2tb drive and the original 2tb drive that is staying.


I also have another readynas duo v1 4.1.10 that I use to sync between both readynas. This readynas has a 500gb drive and a 1tb drive. If I take out the 500gb drive and insert the 1tb drive from the first readynas (that is getting the 2tb drive)
will the data sync. The 1tb drive I will be inserting will have data on it from the first ready nas. What I want is when I insert the 1tb drive into the second readynas, the original 1tb disk that is in already in the second readynas I want that to overwrite the data that was on the 1tb drive just inserted and sync the data from the 1tb drive that was already in the 2nd ready nas to the 1tb drive just inserted. Thanks.

Edit-from the posts I could find the data on the disk I insert into the second readynas will be wiped clean and synced with the 1tb drive already in the second readynas duo just wanted to confirm? Thanks.