Originally Posted by
delbiker1
The fraying cable will always screw up the shifter eventually. The new cable will almost certainly solve the problem if all the rest is correct. I would suggest replacing all cable and housing if they are all that old. I apologize for missing the obvious cable issue. I was assuming, and I should know better, that you were installing a new cable.
I fall into the assuming pit too often myself. It's so easy for me to go past the most basic first steps of a problem repair, the steps that most any experienced wrench knows blindfolded. I am often reminding myself that most here don't have the depth of understanding and experience that a few do and, thus, often don't supply needed data or miss reporting small but important details. Andy