I posted this on the other thread started by Yogi, but in case you don't see it here it is again -
A few weeks ago to monitor the halfshaft gap to the housing, my mechanic made up two gauges out of aluminum that fit the gaps tightly (one for the left, one for the right hand side). Checking with the gauges I noticed the right hand side gap was increasing slightly. (you other owners may want to get your own gauges fabbed - only takes a few minutes)
As a result, I just had my bolts all replaced yesterday. The tech drilled the new ones and safety-wired them too. As it turns out, the car did have the black hardened washers on the inner connecting bolts. But better to be safe and not have to worry about it. It was all free anyway, because the tech is the head mechanic and he had read this forum so he agreed to do it as a safety issue. BTW, my car is an early '06 serial number 0724.
BTW, my technician found a few things were loose on the car on his inspection. He found one wheel was loose; he found some screws on a brake caliper were loose; and also he found the left rear axle bearing nut was also very loose!! So boys & girls - get all those parts inspected and re-torqued after you've put a few miles on them. Ford has apparently sent bulletins to their dealers about it just recently.
Again, many Thanks to this forum, and all the guys who pm'ed me about this. Without you I never would have known.