R&P gear sets?
 

Any USA made gear sets available these days? Any brand better than others in term of ease of set up, quietness, etc?

I see RA sells Yukon, Dana, US Gear. Someone recommended Revolution Gear but I have never heard of them.
I realize proper set up installation is key with any gear set but I am in need of new 3.42's for my 8.5" ten bolt and want a quality made R&P.

I've used US gear which is suppose to be made in the U.S. They have been very good gear sets. Moser uses them. says High Quality Gears Made With Pride In The USA

I've read here on the forum somewhere that Motive are supposed to be the quietest, and based on that used them. They are made in Italy. No noise at all out of my set. I have know some people who used Yukon's and complained of noise.

With new gears from GM, can I use a gear set from a newer GM 8.5" rear end such as a 2001 chevy 1500 pickup truck? Will those fit an older 1981 2nd gen rear end?

GM lists a 3.42 gear set PN 23114031 for a 2001 silverado with 8.5" rear.

Is it the same? Pinion diameter, ring gear bolt size, etc?

AAM is the GM supplier. I just had a new set of AAM 3.42 gears put in my 8.5 rear.
AAM = American Axel Manufacturing.
I did not buy them from the dealer, got the shop doing the work to supply.

Pretty sure the answer to your last question is Yes the gears are the same.

US Gear was made in the USA, but US Gear was bought by Meritor and they dropped the ring and pinion product line. Any US Gear ring and pinion sets you may find were made a few years ago and are still on the shelf. Motive and Richmond are both made in the same factory in Italy. Most of the others are made in China or India. The aftermarket does not produce enough profit to make it worthwhile for the big companies, all they care about is maximum profit they don't care about people.