I've had to do the seals on my E-Hoe (JCB 3CX), it's not too bad a job. Sounds like your JD may have a similar set up to my 3CX. The hydraulic oil was pouring out of the cylinder on mine and not the hoses, not bad for the original seals and 6K hours on it.
With the JCB, you can get the E-Hoe cylinder out without removing inner dipper as long as the top pin on the cylinder will come out. The bottom pin came out easy, however there was no way the top pin was coming out (despite many hours of trying). There is no factory fitted grease nipple on the top pin of our model 3CX and it had rusted solid on one side of the dipper. With our machine, we extended the dipper far enough to get at the C Clip holding the bottom pin, tapped the pin out and then retracted the cylinder with the plan of lifting the cylinder back toward the machine and out. When we realised we couldn't get the top pin out, we decided to re-pack the cylinder in the machine. We worked out a safe way to slide the inner dipper out far enough to lift the cylinder up to work on it. We found that removing the bucket and using it as a chock for the Dipper gave a us a good working height and a solid base to rest the dipper on. With some H/D ratchet straps, a couple of heavy axle stands and a trolley jack, we slowly slid the inner dipper out. Once we had the inner dipper out far enough, we then tilted the cylinder up and chocked it to allow us to re-pack it in the machine. At least with the cylinder held firm by the top pin, it was easier to crack the gland nut and then withdraw the rod. We just reversed the procedure to put it all back together again. The ratchet straps helped too as we could safely tighten the straps to "winch" the innner dipper back in far enough to get the bottom pin put back in the cylinder. Once you have it all hooked up again, just remember to exercise the e-hoe back and forth to get all the air out before you use the machine for digging. Just some ideas if you aren't able to get the cylinder completely out of the machine for some reason.