Well this is one of those precedures that takes about 90% of the job time to access the seal and about 30 seconds to actually install new seal. If you have a decent selection of tools you should be able handle it. I would recommend a good roll pin punch set for removing the roll pins that hold the linkage arms onto the shafts(brake shaft, diff. lock...)
To sum it up, you have to drain hydro fluid, remove wheel, fender, section of roll bar (if your roll bar is not folding you would remove whole thing). Disconnect any linkages, and remove roll pins and slide adapters off shafts. After you make certain everything is out of way, support tractor with jack stand under center transmission housing because you will have to unbolt axle housing from transmission housing (24mm or 15/16" socket) and slide housing away from trans. housing. After seperating, stand axle housing with gears facing upwards and remove large snapring holding large ring gear to axle spline. Pull ring gear up and off then you can pull axle from housing. Then remove seal protection plate and pull old seal out. Install new seal then start reassembly which is reverse from dissassembly.
Some advice or tips:
sand any rust off shafts (brake, diff. lock ect..)and lube before unbolting axle housing.
Study how everything you are removing is installed. Or the easier thing to do is take some pics because Im sure you will be questioning things during reassembly.
Mating surfaces between axle housing and trans housing use a liquid gasket so you will need to make sure to use recommended sealant (john deere form in place gasket)
Make sure you clean both surfaces with razor blade and remove all oil from surface before applying sealant. ( I would run a small bead of sealant on both surfaces)
Dont tighten axle housing bolts unless your certain housings are fully mated together. You may have to slightly turn axle shaft to allign gears.
Ask your dealer if they would print out a copy of the procedure for you.
Finally inspect seal and axle for damage while dissasembled. Apply a little grease to seal and axle to aid assembly.
Good luck!!!
