Dull Grinding? Noise from Front End

Hello, after an incident with being submerged in water for quite a while, I am starting to hear a dull noise(almost sounds like loud tires) coming from the front of my 91 cherokee. Sounds like non lubricated differential in front. Ive changed all my fluids, tranny, oil, diff's, t-case fluid, and it still makes that noise. It gets louder with speed, not engine RPM. This sound also started coming from my friend who drives a 99 grand am after he drove through a really deep puddle. Yesterday his #2 cylinder blew through his block. Dont know if thats a coincidence or not. Anyways, anybody have this trouble before? Could it be water damage in the engine? Thats the only problem im having with her now, and I dont want any pistons blowing out or anything. Thanks, I really appreciate the help.

Unit Bearings!

Eep, what are unit bearings? Oh, I know I have a broken U-joint in the front left tire, but its been fine for a while, i will change that soon. Has nothing to do with it does it?

Never heard unit bearing before, but it sounds like it may be you hub bearing. Jack it up high enough to get the tire off the ground, grab the tire at 9 & 3 O'clock, try to wiggle it and see if you get any movement.

Brake caliper or pads, that bad U-Joint though could tear your front out though.