I had same issue with my 2000 AWD astro. Straight driving no issues but when I made a tight turn the van would shake and the front wheels would bind. Turned out to be the transfer case. You could remove the front drive shaft or rebuild the transfer case. The broken transfer case cause damage to the front diff and axles. I was able to source a good front diff on ebay at a decent price. I had a transfer case from a 2007 Trailblazer SS which fit and bought new front axles and hubs. Drives and turns excellent now. Perfect solution for my needs and budget. I got to use some parts from the garage. The tb SS transfer case is very strong and is made for high performance. It should out last the stock unit. The only issue is that there is no provision to bolt up the torque arm from the engine.
My 2007 tb SS does not have any torque arm and is putting out over 480 hp