Yep, the Detroit locker does require a resetup of the gears. My point being that there is no control over the thrust washer clearances in the 4 pinion v6 case. If you're stuck with one, just pay the $200 more for a case unit and the $150-200 to re-setup the gears. The thrust clearance is a very important check and adjustment made with a 2 pinion case locker. Aussies are good lockers because of the manual setup of the clearances. Theoreticly the lunch box unit in a 4 pinion should be fine since the factory setup with the thrust washers are being reused, but as I found out that just isn't the case. However, you can get it "right." It just requires you pull the 3rd, install the locker, put it in the truck and see what happens. If there seems to be too much play before the engagement of the locker, pull it all back out and apart and try a slightly thicker thrust washer on one or both sides. OR if it's not really unlocking, try repeating with thinner thrust washers. Then repeat till you're happy. There just isn't a way to tell, even if you bench test the locker prior to install, it could still be either too loose or tight.
Now for my problems, I got new pins, re-installed and still it's not really unlocking. Seems in a turn it unlocks, skips a few teeth then locks, unlocks etc. but all seemless so it just appears to drag the tires. BUT I know from other full spools that there is no way it's fully locked during a turn, not to mention that when ALL the pins broke after a day on the street it was then fully locked in turns . For now I'm watching tire wear and it's even with the front, so I'm not spending a weekend tearing it down and **** again, just to take the chance the results will still not be better or to far the other way. Plus I'm not keeping this truck for much longer probably, so someone else can either hate it or love it.