have a stock o2' ctd, no mods, have @65,000miles(116,650km)and just saving some scratch for a few upgrades on the tranny, question is what should be the first thing to get if any?

 

I would think the first things to upgrade would be the valve body and the torque converter. Your best bet would be to contact some of the transmission builders whose names you see mentioned on this site and get their opinion. Most will try to match the transmission build to what you will be doing with your truck (stock, towing, pulling, drag racing, etc.)