01 automatic 4wd. Coming up on 250k miles. Never done a proper service, but have always watched the level and kept it at cap.

I have owned it for 20 years. So I know there has been no abuse.

can’t seem to find an absolute answer on of I should drain and replace the fluid or not.

Absolutely YES. The idea that new transmission fluid will harm your transmission is an old wive's tale.

Clean fluid is what your transmission needs.

No need to drop the pan. The "filter" is just a metal screen. Either drain and fill, or follow the direction in my sig #3 for a complete fluid replacement.

Use Dex/Merc only. The auto parts store might tell you to use ATF4. Don't do it. The transmission manufacturer has never recommended anything but Dex/Merc. Chrysler decided they needed to sell more of their proprietary ATF4, so they recommended it, and that is in the systems at the auto parts store. It's wrong.

Dex/Merc only!

Like said, Dex/Merc III. Nothing else. Ever.

if I am draining the Tran pan cold, about how much should I replace it with? Should I do it again in a week or so?

X2 on not using ATF4+. Pour what you drained into a gallon jug, and put the same amount back in. Then check the fluid level. I'd probably do a couple of these partial changes spaced out a week or two.

Also google for bleepin Jeeps video on checking and adjusting the throttle body to trans cable.

In case anyone missed it, Dex/Merc only. buy a gallon. Put 3 quarts in, warm it up and follow the instructions on the dipstick when topping off.