Need a little help adjusting either my cruise or the trans. When in cruise the car doesn't shift down when going up a hill, it just dogs along in overdrive. It worked fine before I messed with a vacuum line that ran to the cruise control. The line was plugged, I thought it had broken off somewhere so I took the plug out, then the cruise wouldn't work, so I replugged the line. The cruise works but won't downshift. The car will down shift when not using the cruise. What do I look for and what can I adjust, my manual says practically nothing about the cruise system?