I have no way to measure the actual preload (as in the pounds of force required to clamp the two halves of the differential carrier together). But, I did make a rough measurement of the torque required to slip the limited slip on both rigs. The one on my original Raider - which doesnÆt seem to lock-up as well as it used to with parking brake application - had a break-out toque of around 75 ft-lbs and a sliding torque of about 50 ft-lbs. The one out of my Montero parts car (which is the one I took apart) had a break-out torque of about 50 ft-lbs and I think the sliding torque was something like 30 ft-lbs.

Thanks for the tip on groves in the carrier housing. It does have some minor groves, but I think I can remove them.