The little bolt/pin that held the cross shaft (technically it's the spider pinion shaft) failed. This in turn caused the cross shaft to slide out. The cause of the bolt failing remains a mystery to me, but I've seen more than 20 in life and they were all GMs. I saw one happen at 35 mph driving 20ft feet away from me. At first, I thought maybe they missed the intersection, but nope. Cross shaft through the rear cover.
A forum community dedicated to GMC and Chevy full size owners and enthusiasts. Come join the discussion about Silverados, Sierras, and other full size trucks performance, modifications, suspension, lift kits, tires, maintenance, and more!