It may be advisable. But several reliable sources always say to leave it be. I do know it is one expensive bearing. So if there is any tendency to cut corners this is one that few will fault you for. If there is any notice of reason when examined of course at that point you should change it. The front bearing on the output shaft is the most failed bearing in the 5 speed. This one has to be changed. Do you have the use of a suitable press for changing the bearings?