RE: 318 upgrades...and troubles (update)
The high shift points and dropping out of gear sure sould like a low fluid issue.
I dont believe in a fix in a bottle, but I have great results with LubeGard products in older transmissions.
The kick down can be what is making the shift point higher, but with both problems.... It wont take the transmission out of gear.
I would be happy to walk you through a sure fire way to adjust the kick down, but I would not advise leaving it loose and shifting manual. At very least pull it half way back and wire it. Drop me an email or PM and I will give you my desk line if you need advice on the adjustment.