Thanks for the update, Rich. We would certainly like you to continue this thread, with pictures, as you diagnose and perhaps repair that transmission. We do not have detailed repair threads on hydrostatic transmissions, and this one would be very useful for the archives. Of course we will help if we can.
From the thread on the transmission repair in that other forum, it sounds as if you need to make personal contact with the transmission manufacturer, and explain your problem (after you have found out pretty accurately what it is). Phone is best, but prohibitively expensive unless you have the right kind of phone plan. Most likely email is also possible, though. Whether TuffTorq will ship parts is one issue, but what they would have to charge for shipping is another.
I notice that the repair manual for a Poulan ride-on that uses the K46 transmission, says "Order parts from transaxle manufacturer", so my guess would be that TuffTorq is experienced in dealing with this kind of customer enquiry.