Been searching forum, haven't found quite what I am looking for. 84 300d, pulled plug in tranny tonight bc 3 months ago when I changed filter and fluid I put too much in, dipstick showed over full Drained out 3 qts, put in 2.5, shows full but now won't upshift into 2nd until 3500 no matter how light on throttle, won't do 3 and 4 until it hits rdline, 4700. Always shifted hard, now slams gears at only at high rpm. Wonder it some junk fell down funnel and stuck somewhere it shouldn't, other thoughts? Would a flush help??