Trans problem

[P_Knight]

Well yesterday I'm driving down the expressway and suddenly it feels (and sounds) like I'm driving on the rumble strips. I pull over thinking maybe I lost a u-joint. Look under the truck to see fluid pouring from the trans (pan area). Was hoping to limp it to a safer area, but couldn't get the truck out of park. Shift lever won't budge.

I know I won't know for sure until it's opened up, but any ideas what may have happened.

 

[RMacneil]

If you lose too much fluid, it won't shift. You said it was pouring out, and that sounds like plenty of fluid loss to me to create engagement problems. Maybe your pan bolts got loose and it's simply a fluid loss issue. The torque spec for them is really low, like 12 ft-lbs or so.
I'd verify where the fluid is coming from. If it's from the pan gasket area, snug `em up, add more fluid, and see where you're at.
Good luck.