904 3 speed transmission acting funny

Without hearing it, it's hard to say. Gear type noises in an automatic are not a good sign. It usually means a hard part is going bad and the trans has to come apart. If it's a fluid noise, it will depend on what is causing it. An overfill will not normally cause a noise. It usually just makes the fluid foam up and squirt out various places. A low fluid condition will cause a whine as the pump cavatates. That will go away as you fill the trans to the proper level. Did the noise happen all at once or have you been working on it?