Weird vibration

Hey, I've got an 86 blazer with the 4.3 in it, And starting a couple days ago, Everytime i get up to about 45-50 and up , i get this really bad vibration, I sorta remember that when it started it was all pretty sudden, I goosed it earlier tonight after it started doing it and it went away when i hit about 70 or so, But just for a second, I let off the gas and i heard this deep almost humming noise like something was slowing down or somethin, But that was the only time its done that, Plus i've been getting this really annoying humming, Like somthing is spinning , and it gets faster as i move faster, and slower obviously when i slow down, And help on any of this would be most appreciated, Thanks a ton in advance.

Vibration at highway speeds isn't really unusual on S-10s and Blazers. It would seem as though it would be almost normal.

Really ? I've heard alot about them having vibrations at highway speeds, But the thing that concerns me is that it wasn't doing it before,And the vibration is pretty bad, But i dunno...

Really ? I've heard alot about them having vibrations at highway speeds, But the thing that concerns me is that it wasn't doing it before,And the vibration is pretty bad, But i dunno...
I agree with airforceone! But get your hub and bearings checked out, someone else in the forums was having a similar problem. I had a dodge neon once that had the exact same problem your having. Speed up and it sends a quicker noise and the slower i went the noise would slow down until I went below 25mph then it would stop. It ended up being the hub and bearings.

Heheh, I figured out what it the vibration was today, Apparently the vacuum coming off the transfer case was on wrong, It wasn't letting my front end disengage :( , I would like to thank everyone for their help =)
My day was incredibly great when i fixed it, Then went and watched a movie, And backed into a telephone pole... Takes intelligents to be me,
I swear...

Does your truck have the tailgate-mounted spare?

At least I know now what to look for if I had trouble with vibrations.

No it doesn't, I hadn't gotten it yet, Its all in a nice " V " shape now =(...
Gonna take the bumper off and try and bend it all out best that i can until i can get a new bumper and tailgate.