check your drivers side motor mount, i was having the same issues that you describe earlier this week up until today, and suspected the brakes, front diff, trans, and hubs. none of them were the problem, my ds motor mount was separated and had cocked the engine side ways almost permanently because the mount was stuck on top of itself. once i lifted the engine and got the mount to sit back the way its supposed to all the noise stopped. the noise that sounded like rubbing/grinding was the engine vibrating against the firewall when the engine was under a load (braking.