The Ranger trans pan gasket has been replaced, the trans cooler hoses were leaking so they were replaced and I ordered an entire gasket kit for the engine. My goodness I was shocked, the valve covers and/or intake are leaking oil and it's covered both side of the block, the oil pan is leaking, the rear main seal has been leaking for a while. Thinking we'll pull the engine out to replace the seals, ugh.
The original transfer case for my Expedition now has new bearings and seals. What a difference between mine and the salvage yard unit. Mine was clean inside with nice red fluid, which I knew, the clutches look really good in comparison and had no pealing of the anodizing, and far less wear despite having 60K more miles on it. I don't think the fluid was changed much if ever in the salvage yard unit, so maintenance makes a difference. After I reassembled the salvage yard transfer case I thought it felt good, but the original one is so much better. Smoother, quieter, easier to turn. This bearing and seal kit had different bearings and that may be part of it. The other thing that surprised me is how easily the case went back together this time. I fought with the salvage yard unit to get it back together, this one just fell together quick and easy. Picks below for comparison.
I don't think the remaining vibration is the transfer case, but next weekend I'll swap the original back in and find out. With any luck I'll also get to repair the rusted trans cooler lines. The plan is to cut out the rusted part of the lines, bubble flare the ends and slip some hose on.