I would suggest that you remove the roll pin that holds the gear onto the shaft at the bottom and then remove the shaft out of the column - that way you can see if the shaft is worn or if the hole in the steering column is worn - if the shaft is worn you can build the area up with a bit of weld and then file or sand the weld back down to the same diameter as the shaft or if the hole in the column is worn you can probably make up a steel sleeve or bushing to get the hole the correct size. Check to make sure the hole between the grease fitting and the shaft is not plugged - I had to run a small drill bit through mine if memory serves me correctly to clean out the crud - as far as the lower washer missing you can probably get a thin machinery spacer washer or regular flat washer at the hardware store and turn the hole out in your lathe to make it a nice fit on the shaft. I do not recommend trying to remove the steering wheel from the shaft but if you feel brave you can check out how I got mine off in post # 102 and 103 http://gardentractor...-project/page-7 .
Once you clean the gunge off of the gear you may find that it is not worn as bad as you think - the holes in the support plate that the steering column mounting bolts go through are slotted to adjust the column sideways to remove excessive lash between the lower steering gear and the gear on the shaft - clean the teeth on the lower steering gear out as well and have a good look at them to determine their condition. I find that if you gently lift up on the steering wheel while you are adjusting the column you should get a good gear teeth mesh - snug the bolts and then try turning the steering wheel from lock to lock and make sure you do not have any tight spots - if you do then you can readjust the column a little bit to get more clearance. On the 1053 am working on I did build up about three teeth on the lower cast steering gear by welding them with the mig welder and then shaping the weld using a die grinder disc mounted in an electric drill - you may wish to try that or try and find a good used set to replace yours with.
You can see what the lower gear looked like on my 1053 in post # 83 here http://gardentractor...-project/page-6 - and in post # 85 you can see what they looked like after I welded them.
If you check out post # 96 you can see how I removed the lower gear on the shaft http://gardentractor...-project/page-7 - and if you go to post # 108 you can see the brass bushing I made for the top of the steering column or you can probably buy the correct nylon one from one of the site sponsors.
You can also check out post # 123 and see the bushings I made for the idler arm that pivots on the PTO shaft - http://gardentractor...-project/page-9 .
Hope this helps.