Hey Jon, Your TV cable is incorrectly adjusted. That adjustment is the key to making a 700R4 behave correctly. Don't keep driving it like that, you "will" Smoke the transmission. Check out Bowtie Overdrives. Their website has lots of info on these transmissions.
The wire that plugs in to the tranny is for the lockup converter.
What carb are you running? That could be part of your problem.
some carbs wont work correctly with a 700R4 unless they have the correct brackets & cable set up. Bowtie overdrives makes & sells kits to properly set the TV cable up to most of the popular carburetors.