I consider trac-loks to be disposible diffs. They don't work particularly well, the clutches are typically worn out in less than 40K miles, the case is weak, the spider gears wear out quickly- all the edges get worn off like beach glass. (They are said to be improved now.) New spider gears and clutches will cost within $50 of a new unit (less than $200). It offends me that vehicle manufacturers sell unsuspecting buyers a limited slip diff with such a known short life.
You don't have to mess with the pinion to install one- only the ring gear, but that still involves setup.
On the other hand the Power-lok is arguably the strongest limited slip diff. It has a tough case, four spider gears, and can be set up so tight as to skuff the tires on turns like a spool. The clutches typically last 100K miles, they are worth rebuilding, setup is the same, and they cost only about $300. Toss the trac-lok.