Mine is the same way. I just had the shaft replaced and its stiff as can be. It's been driving me crazy all week. Turning To the right on higher speeds is the worse. I'm thinking a recessed foot tray might help because sometimes I think I'm too far back, it's a little easier if I'm standing more on top of it.
If that doesn't help, I may considered a minn Kota. Mine is less than A year old. The min Kotas worry me because I hit stumps frequently. But they are easier to steer and quieter. My TM sounds like a tank on any speed over 4 or 5
PB 10.58 Joe Pool