I unfortunately have had pretty bad luck with the Yukon gears. There is no doubt that the Sterling 10.5 is a pretty weak axle but I have been through 3 gear sets and am on my 4th. 2 broken pinions and one broken ring gear. They said it was from shock load. I told em it was 6.0... How much shock can it make? Another thing is that if you ask Yukon who actually makes there gears, they cant answer you because they are made all over.
I am doing a Dana 80 swap for this year and went with G2 gears from 4 wheel parts because of there 10 year warranty and from what I can find, they are made in an old Dana facility. Its not done yet but well see how it holds up.
Matt