Originally Posted by
70sSanO
It is my understanding that the one thing about the Shimano thumb downshift lever is that is has no trim function. When you press it, it will drop down to the next chainring position.
John
I have ST3300 brifters and they definitely have a trim position with the thumb switch. You can press the thumb switch down half way and it’ll move the FD slightly to the left.
Anyways, to the OP: you should definitely take the brifters apart, flush out the old grease and lube with new grease. They all get gunked up with age.