Transmission making jerking movements in reverse and slow gear changes

While backing up I noticed sometimes my car will delay or make jerking movements in reverse as opposed to clean reveres. While I was driving my car felt “heavy” or that it stayed in a gear for too long while trying to drive. Yesterday I took my car in to see if the previous owner serviced the transmission fluids and the tech said “there are no records of the past owner ever doing a transmission fluid job”

So my question is, is my transmission making jerking movements in reverse and slow gear changes due to lack of transmission fluid (my year car does not have a dip stick so I would have to drain the pan to check) or do I have my serious concerns? Giving my harmonic balancer had been replaced earlier and could have damaged the transmission?