What is normal IS response from a 28-135mm Broken?

I have had many lenses both Nikon and Canon with IS/VR so I am very use to the way IS works. Normal use gives kinda that wave "sea sick" feeling as it works to stabilize so I'm use to that with a little Huuuuuuu sound but my 28-135 seems a lot different.

I just bought it today and I'm a little uneasy about this one. I see the normal IS wave and sound working BUT when I aim the lens down at 135mm slowly or fast I get quite a large sound of BUZZ and I can actually feel the buzz in the entire body through my hands! I can also see the lenses elements vibrate quite quickly instead of the wave like motion I'm use to. This is quite a Buzz if it is normal.
If I move up,right, or left it works normal but down is violent ha ha!
I know this is an older lens so the IS technology was different and I have read about a bit of a buzz sound but I'm wondering if this is when you move the lens in all 4 directions or just down like mine.

Anyone else with this lens have the same experience?
Thanks

mine does that too. considering that the elements are spinning to stabilize the image it makes sense that it would not like random fast changes in orientation.

for what its worth, mine has been doing this for a long time, and I've had no issues. I did stop jerking it around with the IS on though

mine doesn't do anything different when i point it down

Hum ok thank you both. I did a bunch of shooting and Pol24 you say the elements are spinning, if thats the case then it makes sense that I could get some vibration like that. I don't really know how the IS works.
It seems that when it settles down I am getting good sharp photos and the IS responds normal but if I manage to snap the pic when its having it frenzy then the images are shaken.
I'm just considering returning it which will cost me shipping and buying another lens or just working with this blip. Its good to know I'm not the only one.
Thanks again both