Were you only experiencing shaking at a certain speed? My drums were bad warped and shook at all speeds. Changed it all out last week and now it only shakes around 40mph when braking. I didnt think to suspect the u-joints and wont get back to my truck for another 2 weeks...
It had a low speed squeak/grind in forward and reverse. Shaking would start about 40, then fade away after 50, but I could still feel a grumble in the body, through the seat. Also only felt it while under acceleration/steady throttle. If it only shakes while braking, that seems to indicate a brake issues, but it's not too hard to drop the driveshaft(s) and wiggle them, for peace of mind if nothing else.