Maytag washing machine over agitates on spin cycle?

Washing machine agitates loudly with a lot of vibration on spin cycle which causes machine to shut down and stop.This is an older machine and seems to do this with both heavy and lighter loads.The vibration is very loud and causes cycle to shut down until manually restarted.Any body have any ideas? Is it fixable or do I need to call 'the $repairman'.Help