Gearbox replacement codes

[paulandpatrick1]

hi there everyone, we need to change our gearbox on our 2015 Ford transit custom (2.2 diesel FWD), which has the code fk2r-7002-cqa. We are finding a lot of replacement gearboxes but the three letters at the end of the code are different for example fk2r-7002-dga or cga. I was just wondering if anyone knew what these letters at the end meant and if these are interchangeable or if I’d need to get the exact same code.
Thanks In advance