I've been posting all over to get some insight on brand names for gears and am equally befuddled. There's Genuine Gear that offers a lifetime warranty regardless of what went wrong (even poor install) and is reasonably priced. For the Dana axles there is always Spicer gears (oem quality) if they have the ratio you want. I believe Precision Gear and Genuine Gear come from Italy. They do make some fine metalurgy in Italy, but who knows? How can they offer a lifetime warranty against any abuse? Are they just plain cheap and that's why they can replace them? I've bought tools like that and they are not worth the effort.
In the end I went to Drive Train Direct and bought their "Power Pack" for $419.00. That's gears and install kits. The gears were Spicer in the rear and Superior (also US made) in the front. They would have been spicer all around, but Spicer doesn't make 4.56's for the Dana 30. The install kits from everywhere I called all use Timken bearings, so there should be little difference. Most people tell me that Spicer / Dana gears are the best and that all else are just copies. Hmmmm. Well, I bought into that and went Spicer. Gears seem to range from $115 a set for Sierra's from West Coast Differential to around $189.00 for Spicer / Dana from some sources.
Good luck with your hunt for quality and good prices. The $419.00 seems like a good deal to me for brand name parts.
Tim
84 CJ7, 258, HEI, M/C 2100 carb, 5 inch lift, RS9000's, 33x12.5 BFG M/T's, Lockright, full cage & belts, Xenon flares, AMC 20 1pc axles, GM dual diaphragm brake booster