Hard to tell where it's coming from, but the truck develops a vibration at ~45 mph. It's done this forever, been through a couple sets of tires so that's no it, had the drive shaft balanced, new shocks, just can't find the problem. Any ideas?

thanks

 

Wheel bearings and ball joints?

 

My 88 and my 91 both shook like a bastard at highway speeds. Changed the motor mounts/front diff./frame mounts...its a three way mount. Motor to front diff to frame. The rubbers wear out and allows the front diff to "float" around ( you'll hear a banging noise from the front end on bumps and corners sometimes ). It knocks your front axles slightly out of alignment, causing a vibration.
If you have a good look, you can see the rubber gone from the mount.
I could be wrong, you may have something else going on there...but it worked for me...twice.

 

Oh..hey, sorry. Just realized you have a 2 wd. Disregard my comment.