strange vibration

[b2rich]

as some of you may recall i was going to change my ball joints after talking to my mechanic at home. im now in nor cal and have talked to a couple of other repair shops and the confirmed what i thought. my mechanic at home is full of
ß˙ˆ†. and he wanted $875 to do a $:450 job.
heres the thing. I get a vibration between 30-40. after that its gone. when i go over a crease in the road or over any crosswalk i get a rattle and vibration. i think its coming from the rear end now.
tires are good, about 95% and have been rebalanced.
i know im asking alot but does anyone have any idea what the issue might be? and

 

[hopster]

It sounds like a possible driveshaft issue

 

[srteach]

On the rattle and vibration ... check the spring bushings, spring clamps, and bolt torque on the rear axle. Even with good shocks, those things being loose will cause rattle. Bad shocks will cause the noise also.
On the vibration ... ditto on the driveline (and re-grease it), recheck the wheel balance, check the diff oil level ... regular maintenance stuff.
On the driveline ... if the u-joints are bad, you will have a vibration like you have noticed, and as the speed increases, the vibration frequency will lengthen. Usually this can become a 3 to 4 second cycle of fade in / fade out vibration, which can be much smaller intensity vibration. The cycle will be quicker as the u-joints get worse.

 

[b2rich]

so i had a new ujoint drveshaft put in. the mechanic didnt find the problem, but it did take care of some issues. meaning that wasnt the problem my mechanic looked at the brakes. he found a wrapped rotor. turned it down, repacked the bearings put the tires back on( no charge), test drove. and i still have a vibration. but it did take care of the rattle. the pins that hold the calipers were not inserted properly.
we took and rotated one wheel at a time and still get the vibration at 27-35. and its not in the steering. at one time we got the vibration to go away at 27-35. but returned at 55-60 he lifted the b2 up and put it in 4x and the axles dont appear to have any issues. shocks are good.
any other ideas?
oh and the tires are wearing evenly.