Transmission whine noise?

Noticed a whine that is not super loud but loud enough to annoy me happening mostly in 1st through 3rd gear. The harder I take off from a stop, the louder the noise, especially on an incline. I had the transmission fluid drained and filled at the dealership and it didn’t seem to help. It does not leak transmission fluid and I don’t smell a burning smell. It seems to shift pretty well also. The sound is not there when the car is in park or neutral when pressing the gas, or if I have it in drive and hold the brake and give it gas. So, my question is, is a little whine okay, or does that still mean there is an issue? I have no check engine light on. Can it still give a code if I have a diagnostic ran on it? Any ideas of anything else I can check?