If like my 85 300D, there is a filter in the bottom of the reservoir that is easy to replace. Unlikely it would be clogged, but they are cheap. I would suck the old fluid from the reservoir first, just because good to flush it once in a while. Indeed, I think you can run the return hose into a bucket and run the engine to flush most out. Many opinions on the best fluid. I use ATF+4 just because I have it and Chrysler recommends it for all their cars now, even when replacing parts on older cars.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans