With that set up at 3+, do you DD your truck, i.e. put decent miles on it? Another thing mentioned by Greg was, even if the CV is not binding the inner boot can be pinched enough to tear first. Boot should be in good pliable condition.
I DD it, though likely not as much as other people. I take the train to work so it's only used to commute to and from the train station most weekdays.