This is an easy disgnosis. It is so easy, it can be done over the phone. If a customer describes a roaring sound, you can be positive that the main bearings are shot. Front loaders will also make a horrible clunking noise as the tub bangs up and down.
Electrolux With Bad Bearings
The most common cause for lack of full speed spin is a broken tripod. A crack in the tripod casting will allow the tub to shake and make a terrible racket. A tripod is the casting behind the tub that supports it:
Tripod and Tub
Tripod with Cracked Casting
Usually the computer will show error codes for all types of failures except a broken tripod or noisy bearings. However, the MCU may detect something amiss in the shaking of the machine and will not allow full speed rotation. Your ears, however, will quickly find the problem. In some cases the tub may shake enough to damage or burn the front plastic shroud just behind the door boot. Do not attempt to repair a bad tripod or noisy main bearings.
GE Boot and Tub