The first step here grasshopper....My van has not had a check engine light on. I have been using Mopar ATF+4. I went outside to check up on my van , and to see if I have any leaks from my transmission pan, it is a bit wet looking and a bit rusty. I think I might try ,and change the pan with one with a drain plug on it, and probably just change the filter with the pan off the filter has never been replaced . Do you have any suggestions to what filter ,and drain pan I should use (one with a drain plug).
Get some sort of degreaser like purple power at Walmart and start detailing the engine area. Spray it on, let it work a few minutes and then "Gently" hose it off. Everything under the hood should be able to get 'wet' not soaked, not blasted, but with a hose you can get most everything wet.
It is an engine after all, so detailing is more of a concept than a goal, but clean up the greasy pan and engine area so you can determine if you really have a leak and where it is originating from. *stuff under the vehicle, you can hose bast all those hard parts.
If you don't have a place where you can degrease with a hose and the soap stuff, then you can don a pair of gloves, and safety glasses, a paint brush, some old rags and use paint thinner, kerosene, or even gasoline.... I hope you never are a smoker, don't smoke when using flammables..
Don't get a pan with a drain plug for your transmission, not only is it never going to be necessary to change the oil in that again, but if there is a drain plug there, you are going to be tempted.
If there is nothing physically or operationally wrong with your transmission, don't mess with it.
Too much risk with too little upside gain
and potentialy expensive repercussions to boot.
Everything in life leaks eventually.... So yes, you are going to find some "seep" at the transmission pan and perhaps a leak, but I caution you that until you get good automotive working experience in mitigating contamination, the transmission is the last place you want to start to learn.
But I remember when I was young and couldn't hear the wisdom of my elders...
I know professional mechanics who know better than to crack a transmission open if it is beyond their skillset.