[fuzzypuppy]

I'd have to say tires as well, I have had tires that balanced right but when you looked at them spin on the balancer you can see the wobble, as well it seems that if it was the driveshaft that was out of balance bad enough to cause you not to be able to drive it a u-joint, carrier bearing or somthing would let go real quick.that part is just my opinion though. but if you want to check the shaft put the rear end securly on stands so the rears are off the ground have someone get it up to speed while you look under, if it is the driveshaft you'll see as well as hear it you can check the rear tires at the same time as well