The hydraulic units usually stick down pretty hard, I expect they bind on the dowel pins. As I mentioned, I give them quite a snap up on the lift arms to break them loose. You could also try prying between the valve body and the shifter cover. But be sure you do have all the bolts out. Look very closely along the front under the valve body.
The seal you are talking about on the side of the differential case, I believe, is the bull pinion shaft housing ( the shaft the brakes run off of). To replace this seal you have to remove the rear axle on that side, the PTO shaft, and the bull gear for that side. You will then have to remove a circlip from the end of the differential lock shaft, it is under an 1 1/2" long retainer at the outer end of the shaft. The retainer is spring loaded, I use vise grips to push it in, and a screw driver to pry out the circlip. You need about 3 hands to do this and have room for about 1! Unbolt the bull pinion shaft housing, and the housing and shaft should come out as an assembly. The inner bearing of the shaft is pressed into the case, but will come out with a light tap. You should then be able to get to the seal that needs to be replaced.
Good luck, and let us know how you are making out.:thumbsup:
