Drive Train Trouble

[badman]

I have a 2005 LT Tahoe. It has 5.3L with 95000 miles. Have had no major mechanical issues until now. While driving it at about 45 mph it started to make a grinding sound without warning. Turned a corner and it started to jerk and make a loud clanking sound. Stopped the vehicle and moved forward a little but it felt like something was holding it back. Got out looked underneath and nothing visible. Put it in drive trans would engage and attempt to move but wouldnt, tried reverse same thing. turned vehicle off, restarted it and it moved forward and back but had a faint grinding noise, but still felt like something was holding it back. Next morning the same thing. Was towed to the shop and waiting for mechanic to get back from vacation to diagnose. Fluid is full in rearend and trans. Any thoughts?