the detroit is a full lock, the truetrac isnt going to lock completely. if i didnt get the auburn i would have gone with the truetrac since i tow most of the time and heavy. the full lock is nice in the slippery stuff but harder on tires, the tt is easier on tires and a bit more forgiving.
i had broken both oem axles with a detroit first time was in a parking lot turnin tight on asphalt crawlin in first gear, but my horse trailer does wiegh 15k loaded up. second one was pullin up a rocky hill with 12k of cattle got a little spin, hop, pop. but i was pourin some fuel to it when it happened, i probably should have been in 4wd it may not have happened if i was but oh well. i had about 100k with the locker in there at that time and i did break them 2 with in about 2 months. ive got about 150k on the auburn now and really like it alot, its easier on tires and i dont get that binding feel turning real tight.
but thats just me!!