If your washer is making a "freight train" like noise in the spin mode, ( loud roaring ), this is often the spin bearing built into the bottom area of the transmission that is worn out. This bearing is part of the transmission and means a new transmission is required. The noise is usually a result of water leaking from the center seal and bearing area onto the transmission. This water washes out the bearing and it gets very noisy in the spin cycle!! Do check the easy stuff before condemning, nail/pin caught in one of the inner basket holes, nothing is caught in the drain pump, the inner wash basket is not loose and wobbling around. 

See how to take apart info for access to the washer parts.

Once you have the front off, look for water leaking from the center area just above the transmission. Often the transmission is covered with staining from the leak.

Look in this area for the leak

There is a special tool required to replace the transmission, spanner tool part# WX5X1325. The transmission is part# WH38X10002, the seal comes with the new transmission as a kit. Just in case, the seal part# is WH2X1196.

Related link ~ Also see our noise tip for washers and dryers