ok, so I was driving back to Monmouth from Corvallis the other day (about a 20 mile drive) and all of the sudden I had this weird squealing noise coming from the back end of my truck.
On my way back i saw a HUGE gravel pile and decided to drive up on it.
I did scrape a little, but nothing to bad. when I got off I had all kinds of gravel piled up in places. a couple speed bumps later it was all off (I stopped to check every so often to make sure that the gravel wasn't getting anywhere it wasn't supposed to be). A few yards down the road, I started hearing this loud squeal that sounded almost like I had gravel in my disc brakes. I pumped the brakes a couple times to see if the friction would break it loose. nothing. still squealed. I drove it the last 10 miles home. the squeal went away when I was driving above 75MPH for a couple minutes, but promptly came back when i slowed down to 35 in a cop infested city. It squealed all the way into the parking lot.
I decided to take my drum brakes apart just to make sure nothing had gotten lodged in there, and there was noting on either side. so I got my flashlight out, and checked my discs on the front, and nothing out of the ordinary there either. But, my differential was extraordinarily hot. If I splashed water on it, it would sizzle.
Went to drive it this morning (55 miles to Oregon City from Monmouth) and the squeal had gone away, but then it sounded like someone was dropping chain links into a pile of other chain links. (it was constant, almost like gears clicking together, or a tambourine being shaken really fast) I stopped after about 40 miles and felt the differential and if my fingers hadn't been wet from the ground, I'd have burnt myself.
After I got done in OC, I went to a NAPA about 10 miles away,to get some more gear oil, then over to my friends house 2 miles beyond that. I checked the oil level in the diff, and it was not full, but pretty damn close. I topped it off just to be sure. I was also an idiot and added more L/S additive, so now I have almost twice what I need in there for the amount of gear oil, but I don't think it will be a problem.
While I had the truck on jackstands at my friends house, just for ***** and giggles I turned my truck on and put it in gear, just to see what happened. Both wheels started spinning, but the D/S was considerably slower, then eventually jerked a little bit and stopped. the P/S kept going. I put my foot on the P/S to make the drivers side go, and sure enough, the D/S slowed back down to a stop and the P/S picked up its speed again.
From what Trevor and Shane said, here are my possible problems
Bad wheel bearings
Low diff fluid (checked that, not the issue)
I'm leaning towards bad wheel bearings, but wanted some extra input before I spend money/time on this. I am extremely strapped for cash right now and need to get it right the first time.