Ok I got the balance checked yesterday and it seems to have done the trick. Both tires were off by .75 ounces according to the guy. Not sure how much of an effect that could have had. Still gonna lube the u joints and check the fluid in the axle.

Speaking of which does anyone have any tricks for draining a ford 9"? There's no drain plug and no removable cover and I would like to be able to change the fluid without removing the third member