I've seen the numerous post on the Titan rearend failures but I can't remember ever hearing of an Armada having a rearend failure. Our rearends are different than the Titan...I'm 99% sure, if I'm wrong SCR38 please correct me.
Our housings are different because of the IRS on the Armadas. However, I think the internals are about the same.
The failures on the Titans have been in the spider gears. I haven't heard of any ring gear/pinion faliures, or bearing problems.
There may be a reason the Titans are seeing failures and not the Armadas. When you are driving in a straight line without wheel spin the spider gears don't rotate. But if you have one wheel spinning the spider gears are rotating very fast. I think the Titans get more wheel spin than the Armadas, putting much more demand on the spider gears. The Armadas have less wheel spin for a couple of reasons; more weight on the rear axle and the independent rear supension. The Armadas have better traction than the Titans. Also all Armadas have VDC and Torque Control which limits wheel spin, many of the Titans don't have it.
I don't like the construction of the spider and side gears. They are powdered metal construction, not machined from a steel billet. While powdered metal technology has come a long way I would still like to see the spider/side gears machined, like the ring gear and pinion.
I have an 04 Armada without the tow package. I tow a 25'tt that weights around 4000lbs loaded. My rearend went out on me when I was coming back from a camping trip. I did the up grade to synthetic fliud before I even towed this camper. I had 10,500 miles on the rearend before it went out. I also have an 05 Titan that I tow with now, so far no problems yet.