I have been chasing a vibration on my wife's lx470 since we bought it 3 years and 40,000 miles ago. I had actually chalked it up to the 8 year old set of michelins that were on it. Its more of a grrrr or drone that you feel in the floorboard and only over about 60mph. Replaced the tires last week and the noise/feel is still there. Finally decided to pull the drive shafts one at a time and drive it with the CDL button pushed. No change or possibly a little worse with the front drive shaft out. Noise and vibration completely gone when I pulled the rear drive shaft and ran only on the front. So, here is were I need advise. Both the spiders on the rear drive shaft feel perfectly smooth and there is absolutely no play in them. The rear is a little more free than the front, but even if I pry on them the they have absolutely no slop. Also, the weights are welded onto the drive shaft, I could not find anywhere that one may have came off. The two parts are in phase and the factory? paint marks on the flanges are lined up. I searched a lot of old post and found people cautioning changing u-joints when there not bad. A few ended up with vibrations worse than they started with and at least one ended up having to replace the whole drive shaft assembly. Is it possible that the drive shaft has been out of balance since it was new and the previous owner just ignored it? Is it possible that it just went out of balance on its own? It has never been off road and there are no marks on it that would make you think it could be bent. Or, could this be indicative of a bigger problem with either the bearing on the output of the transfer case or the input of the rear differential that only really gets noticed with the drive shaft in? What about rear wheel bearing, would they only make noise if the drive shaft is in? We don't have any decent drive shaft shops withing 50 miles or I would just go get it balanced and see what happens. Thanks...