We've also had a few issues with the ring-and-pinion in the back of the Avalanche. We realize now that going from the stock rear 14-bolt to a low-pinion Dana 60 was maybe not the smartest idea. (The 14-bolt has a 10 1/2-inch ring gear over the 9 3/4-inch 60.) But then to add weight and traction on bigger sticky tires only compounded the problem. The first gearset was not broken in as per instructions and was found busted after The Carnage, while the second set was being abused on asphalt when they gave up the ghost (power braking a 9,000-pound truck can break things), so we are willing to take the blame.