Reality is they were quiet as a mouse for the first 100 miles......then I went on a long trip avging around 70 mph...
I didnt give them any chance to cool down and after about 150 miles on the hwy they started howling....DOH!!
Ill know more when I drop the diff...but at this stage installation error is the least likely cause... The guy that set up the diff does rear axles for our = to SCCA...he knows his stuff.
Ive almost certainly cooked them...
Im not going to point fingers at the quality of the gear set....they were supposed to be Yukon.....but thats another argument for another day.
At this stage any diagnosis is premature.....
Thx for your thoughts...