It does not appear that the transmission fluid has been changed?

Hello, I'm Danny.

The information they gave you is correct. If the car you bought used has not had routine maintenance performed like transmission fluid changes that can cause problems later on. What happens is when the transmission fluid has been neglected or not changed the fluid can become burnt or contaminated. When this happens the material from the transmissions internal clutch packs becomes suspended in the old contaminated fluid. If a transmission service is then performed and fresh, Clean, New transmission fluid is introduced then the transmission will begin to slip or prematurely fail due to the lack of friction material on the clutch packs from being lost with the fluid change. It is normally recommended to leave the old and contaminated fluid inside until a plan is made to rebuild the transmission or any other future repair plans.

However, for any that visit this page that need to have the transmission serviced, here is a guide that will help with that.

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Hope this helps and thanks for using 2CarPros.