Sounds like you will have to install a seal kit, as a minimum amount of repair.

See if you can tell, if any leakage is coming from the "ball/marble" inside the barrel; before you disassemble.(would require more parts)

 But my guess, is that #11 is leaking at the most rearward area.

BUT, reading on here and speaking with JD parts guys (about a JD4440)  they recommended reassembly with #9 and #10 seals (old style) VERSES the newer style of #11 seals.

Reason is that the newer style (#11) tends to seep oil when tractor is sitting still and not running = that was my complaint to begin with on that 4440. {note: I found #11 seals where inside my SCV and I went back together using #9 and #10 = no leaks; but I did reseal the rest of the SCV with other seals in the kit, too}