How do you determine if you have a slightly bent axle?

 

For a rear shaft it's simple. Remove the tire and rotate the shaft manualy. Watch the flange for any wobble. Don't eye-ball the rotor since they can warp and give a false indication of a bent shaft.

For a front shaft (inner) you ned to pull the shaft and lay a straight edge on it.

 

is it front or rear 2wd or 4wd?

 

4x4 and it's the rear I'm thinking about.

I checked the u-joints last night, rotated tires, even spooled the thing out to 80 MPH with the wheels and brake drums off...still the vibration was there. I did not check to see if the axle might be bent a tad...might get to it tonight.