Trans problem

In my 2000 3.8L the trans keeps making a chugging or thumping noise and when ever this happens the rpms jump around. I have tried changing the trans filter with no luck. Any Ideas????

Willydee82, we need more info. Does this happen in all gears, reverse, park? What speeds?

miles/km on trans? miles/km since last filter/fluid change?

One thing that does happen while driving.....and the A/C compressor kicks in......is that you will hear that....and the PCM will disengage the Torque converter and bump up the engine RPMs to handle the extra load on the engine.
This is momentary......and the RPMs will drop back down and the torque converter will lock back up.
This is NORMAL.
Your A/C compressor will be working with the heater controls in the defrost setting (and mine also works in heat only setting).
Now, mine has not been working much lately.....as the A/C compressor will not engage when it is real cold out.......and it has been quite cold here lately.

Hopefully that is what is happening in your case, as it is a normal thing......and is cheaper than if it is a problem in the transmission.....which would need checking out at a trusted shop to get a good diagnosis.