You need to replace the seals (#18 AR84792) for sure. The shaft (#16 R33826) if it has much wear where the seal runs. The bushings and oring (#17 R221297 & A3606R) This is a sub number that makes it like the after market kits. It puts an oring inside the load shaft bushing. So then you have an oring and seal to help keep the oil in.
Here is how to do it
Look at your picture)
1) Drain all the hydraulic oil.
2) Remove the lower three point arms.
3) Put a floor jack under lower lift arm support (#14). Lift it up just a little bit, maybe 1/4 of an inch.
4) Remove bolt (#19) and plug (#17)
5) You can now drive out the load control shaft (#16)
6) Now lower the lower support with the floor jack. When it is down below the transmission case you can see the seal and bushing. Now you reach through from the inside and drive the opposite side bushing and seal out of the transmission case. I have round punch that is long enough to to it. There is not much lip on the bushings so make sure you have a good square punch when you start.
7) Clean the bores up and install the bushings an then the seals. I like the new JD seals better than the Boling machine kits. The JDs is just about the same thing and the bushings are harder. That is the numbers I gave above.
8) Raise the support back up in position. You want to have it shimmed as tight as you can side to side. You want it to ride the side of the transmission snug. You want as little movement side ways as you can get. IF your transmission housing and support have a shoulder worn in them I just grind them as flat as I can and put in addition shims(#20) The thinest JD has is .036. The thinner shims are not a JD part number. I get them from John Day. I have made them too. You can cut them out of thin sheet steal
9) When you get it shimmed as tight as you can, raise the support up and put the draft control shaft in. Make sure you got it through the draft control arm. I always look from the other side as I slide it through. Reinstall the caps and bolts. You are done other than putting the hydraulic oil back in.
When I have one drained like this it is a prime time to clean the suction screen and replace the hydraulic filter. If the oil does not look real clean replace it too.
The draft control linkage usually does not need adjusted but some times it does. I am not going into that here. You need to get a service manual to do that with.