Dishwasher now very noisy, could be the motor?

Over the last few weeks, my Bosch has gotten very noisy. Not when filling or draining but when running, everything cleans okay but I think the motor is on its last legs. Machine is only 4 years old mind. I think this is the problem and I can get a new motor, are these easy to fit? Would be appreciated if anyone has a guid or pointer to any guides. Cheers.