Congrats on your purchased and welcome to the site. The KDP is there to hold the gear cases together, but you are right i have no idea why there would design it so it would most likley destroy a truck:fist: But good thing you are goin to fix it. And the 5th gear nut is also a real problem, You can fix this by putting a couple tack welds below the nut ont the bolt or you can purchase a nut with a set screw on it. But you are doing it right by fixing those problems first. If you have any questions just ask and good luck.
06 ctd,lb,qc,dually,48re,red,all isspro guages,mrbp exhaust.
95 ctd,lb,sc,5 sp,5" stack,8" lift,38" tires, gonna throw some hp this things way.