One thing I would do before you tear into it is to check the level of the washing machine it several directions. We had several unbalanced loads due to too much cloth to one side and this compounded into an issue with the (wooden) floor in our 150+ year old home. Then regardless of what we were washing the washer shook almost violently because the washer was no longer level (front to rear). When we looked at it from the front it looked level to the eye so I thought it was something like members described so I removed the top and you could see right away how offset the "tub" was positioned. I got the level and it confirmed the tilt to the rear, shimmed it level and no more problems. Our spin cycle is something like 12,000(+) rpm from a direct drive DC motor so just a little not being level caused the big problem. Check and make sure it is as level as possible and go from there and try it with a very light load at first or maybe no load at all.

Mike