Flushing transmission on a Chrysler LHS ('99)

Owned since 1999. just flushed tranny and diff (?) --seems to shift better/ smoother. 143K Miles on clock. Last tranny service was at 75K. Just dropped fluid/ filter, then. Great old car. Doing brakes, tires, alignment, tuneup-wires, Struts, etc --so I can drive this thing to 200K miles. Love how it handles on the road. Still getting 28 MPG Interstate at 80 mph with decent power. $2000 in maintenance/repairs is much better than $10K + for someone Else's Lemon. Nebraska

How do you flush a transmission and find a leak for the transmission fluid I have a 99 chrysler we've replaced the radiator got new fan carburetor and now she's not shifting and no fluid