Neptune Washer with New Motor - Seems to have a balance issue

[bio132]

I replaced the motor of my washing machine. I didn't think much of this at the time, but it has been nagging me ever since that the balance isn't nearly as good as it was before the replacement. During the spin cycle, the thing is violent. Significantly worse than before. I've tried leveling the feet, etc. but it hasn't seemed to help. I don't remember a load going through without stopping and restarting the spin cycle. Even when it gets up to full speed (and hasn't tripped the balance switches), it's fairly bad.

I remember having a tough time getting the weight mounted after replacing the motor. Could it be that I put it in wrong or something? I think I remember the new motor having a different weight and it seems the tub sits a little differently now. I have never had a mildew problem before, but after the motor replacement, there is a part of the door gasket (bottom) that doesn't drain well and has started to mildew (it's the lip of the gasket that is on the bottom of the door opening). Any other ideas?

Thanks!

Model MAH3000AWW