just wanted to share how the 05' LS430 (80k) did on our mini Vacay this weekend. Changed out the oil (0W-30) and blew out the pollen filled air filter. tires already rotated and balanced week before. average MPG at 75-80 was about 27. at 70 it was 29. 550 Miles per tank. Car did great as always besides 1 issue.

at 70-80 there was a noticable thump/vibration sound that developed at about 200 miles into the trip. i65 was terrible in some spots and I thought maybe I had lost some weights. so before we headed back I had the tire re-balanced. 3 tires needed an ounce or more of weights. back on the road the thump/vibration is back but less noticeable.

so I have to narrow this down to 3 or more possible problems.

wheel bearing going bad - but this should be felt/heard through all range of speeds?

rear-end differential - perhaps a new type of Dope oil should be used?

rear transmission mount - same vibration issues from worn mounts as the 89-2001 models?

throw some other ideas at me, because I will be tearing her down this weekend. I'm so use to the smooth as silk it is known for and I will get it back