Hmm, we'll the tires are brand new. It did it before I got the new tires also, so I'd hope the tire shop would get the balancing right, especially since they are a reputable one. Interesting though with the exhaust. Maybe, I do remember seeing the exhaust coming out a seam of the muffler one cold winter morning. I would think it would drone all the time. Sometimes it sounds like its oscillating, if that makes sense. It's pretty loud, and always starts at 60. I've never experienced bad ujoints before so I'm not sure. My last jeep had a bad pinion bearing. This is definitely a different noise.
1998 ZJ Laredo, 4.0L, 2WD, it's boring