Speedo Cable

Will ATF running into the speedo cable ruin it?
No, might make the outer sheeting soft, maybe 60 years from now it will fail.

My 67 had been leaking trans fluid from the cable for 40 years. Cable had come in contact with the exhaust manifold 40+ years ago, melted all the sheathing off in a 2 inch spot.

The rest of the sheathing was good but stiff as a 56 year old pop tart