highstrung,

The very first thing to do - check washer leveling.

Second, try anti-vibration pads and third, reduce maximum spin speed using service menu (for Miele 4840 from 1400 to 1000rpm)

Good luck!

It this the W48xx series? If yes, I had serious issues on 2nd floor. I tried adding two screwed together 3/4 high quality grade plywood for the washer and dryer. It helped a little, but still got enough vibrations to add some nice sound effects to SG-1 and made we wonder who slipped the quarter in the sofa slot. Before I did that, I think it would have done some long term damage to washer - not to say of house and nerves.

Also, what I did was dynamic turning. Get a large hard to balance load and adjust the feet for best trade-off while spinning. It helped a little also. At the end, I could live with it - but definitely was an issue.

On other hand, my older Bosch never shook the house, but was smaller. The same size HE5T at 1300 RPM never yet has shook anything.

The Miele's manual said to install on solid floor. I think their spin balancing just goes into brute force spin too easily for 2nd floor. I noticed both the Bosch and HE5t try multiple times to balance, if needed. This gives you a synergistic affect with trying to balance it is also removing some water, which helps easy the balance load. The Miele with plywood, cutting, screwing, removing machines again, dynamic balancing was many hours. New washer took about 10 minutes.

I doubt the HE5t suspension is that much better. Just physics and spinning weight. Just think how small the balance weights on you tires and how much just a little extra water or off-balance affect the spin vibration.

I don't have proof, but I think the best thing is to make the floor as rigid as possible. Adding a soft mat is not a good long term solution. It seems the accelerometer in the machines assume a hard, non-moving floor to pick up out of vibration. If the machines moves too much (or too softly), it just seems to add to the problem. It does not know it is vibrating so much. You could even get a runaway condition- worst case. I seemed to notice this both on the Bosch and Miele. And the reason the dynamic tuning seems to really help, if you can get to the feet while running. Just my thoughts.

Is it on a pedestal? We're looking at a 4840 and sales gal said that they strongly recommend putting these on a concrete pad and that if you can't that you cannot use a pedestal. We were set on the Miele but this issue has put us off a bit.