Ok so I drive a 92 w250 with a cummins, 4x4. About a month ago I noticed it started feeling a little more vibration than usual. I attributed it to the fact that I needed new tranny mounts maybe some new engine mounts. Other than that, everything else seemed fine. About 2 weeks ago I start noticing it almost feels like something is wobbling or maybe even grinding when I've got the wheel fully turned while backing up or turning into a parking space. Plus every so often when I try to back up it makes a squeeling noise. Not every time, but every once in a while. Now I'm starting to get nervous, I have no idea what it could be. I thought about opening up the differentials and seeing if anything is being ground up but with my intermediate knowledge of mechanics I really don't know if I would notice if a retaining clip or something was missing. At best I would look for any metal shavings. So, any ideas? This is the best truck I've ever owned even though it needs some work. So I hate to scrap it if I can help it. I'm not much for giving up on anything so easily. Thanks.