Brands of gears?

Some brands are stronger, some are quieter but they're all pretty much the same. You'll break a front ujoint or shaft before the gears go on a D30 unless your set is defective. About the only way to break gears is with a severe shock load and then the weakest link is what goes, rarely the gears. Theres a guy locally who broke the ring gears but he was in 4lo and winching and the jeep got dragged. Brakes weren't strong enough and the tires turned enough to stress the driveline. Upgraded shafts and joints so the gears were weaker.

I have yukon gears in my XJ.

Yukons in my 44s, think the key is when your talking low gears 4:56, 4:88 or lower. Then the teeth get smaller/thinner and gear quality starts to come into play more. For most people , mid range gears are fine, I hear there are some real cheap Chinese gears around that can get you in trouble.

Steve

Running 5.13 Yukon's now, ran 4.88 Superior's previously, no issues with either. Make sure you also get a good install kit as they are not all equal. Talk to whoever is installing the gears as I know some are preferred over others...