Rockin i have a similar problem with a rubbing grinding type sound in mine . Yesterday replaced wheel bearing, new pads and E brake shoes carrier bearing are good and pinion seems good , I am now going to check U joint . Hell what else could it be . Mine seems to start at 20 mph then gets louder.
97 ZJ PRETTY MUCH STOCK 03 ford super duty 6.0 PSD 4x4 and now a 04 WJ special edition 4.0 QT 2