The typical issue that would cause this is fluid, so I am glad that you had them changed.
https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid
However, when you did was the fluid low or dark in color?
If it was, that is the sign of a clutch slipping which is most likely causing this slipping issue.
The fact that this seems to be doing it in when taking off in third points to a torque converter issue so if the fluid was dark, we are most likely going to have to drop the pan and see what metal or debris is in the pan.
We can also check for codes and if you have solenoid code then that would be the place to start. If not, then this is a clutch slipping and we will most likely have to rebuild or replace the unit.
https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
Please let us know what questions you have with this.
Thanks
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Saturday, March 12th, 2022 AT 5:46 AM