Speedometer Cable Problem
 

After completing an s5 NA to Jspec TII S5 swap on my car, my speedometer cable broke. I purchased a brand new doorman cable and replaced my oem cable. About 20-30 miles down the road and the new cable broke in approximately the same place, about 6" behind the speedometer. What is causing this, and has anyone else every encountered this problem?

My guess would be something is causing the cable to bind and as it turns from the transmission output, it causes the cable to break due to the speedometer side trying to hold the cable down from spinning...