[Oldsguy]

what you are describing sounds like a bad cable and usually changing it fixes the problem. Since the drivetrain is different and you said "as best you could" you are hinting that it may not be the correct cable, right? That might be the problem or it's possible the cable housing is damaged and causing the problem. Maybe the replacement cable doesn't fit the cable housing correctly too, there might be different gauges. Just thinking out loud....