This is 2014 XLT Ecobeast 93 tune TB, Coils the red ones, Side out exhaust, Red line oil. I just got my truck out of the shop The power of just these addon's Broke the transmission shaft broke and the clutch plates had to be replace. I have 152,000 miles at time of brake. Ford did the repair. $3776 for the repair. I run toyo tires. The truck has the get up and go. From most of the threads I have not heard somebody braking the trans shaft. James Fl.

 

From the research that I looked at before putting the Whipple on, the 6r80 weak point is the intermediate shaft, the there's a kit that comes with Exedy clutches and a billet intermediate shaft. I don't think the break is all that common, you probably just got the short end of the stick.