When i first put the 60 in my truck i just bolted it in and didnt replace anything, 500 miles later it shook so bad it made my girlfriend cry, it was nasty, was that bad that over 15 it would throw you all over the place. So i tried the washer trick and that worked for a while, until it started again. Then i noticed a huge crack in the frame rail behind the steering box, then was the time i did, the bolt on , the weld on and crossover. That solved it for a few years then it happened again.....i was pissed, so i did all the king pins,bearings, joints etc...plus added hydro assist. Its been a year now and all has been good even with bias 39s.