Check for broken tub dampener straps at the top of the tub. This video
will show you where they are and how to replace them but you can just feel for them directly under the top panel reaching over the top of the tub to feel if any of them are broken without taking anything apart. If they are ok, can you turn the basket by hand easily? You should not be able to. If that seems ok then take the front panel off and check the 4 suspension rods that the whole tub assembly is hanging from. If ok, run it in spin with the front panel off and try to figure out where the problem is.