Had the same problem on my L2800 when I bought it. Couldn’t get it to free even with a week worth of PB blaster daily so simply bought the replacement from Messicks. It simply unbolts—slide out and slide new one in.
I don’t recall the cost but it was not prohibitive.
Edit: if it is seized and you have to pull it, make sure the internal O-rings are intact to ensure no water can get (or already has) into the transmission case. My external rod was completely rusted and essentially welded to the housing, but the internal parts looked brand new. Now I turn it a little back and forth every time I am using an implement to make sure it stays free.