High mileage auto tranny - change fluid and filter or leave alone?

[Burnsy]

Def drop pan and do new filter and gasket, and around four quarts, get the rubber type gasket nothing else.....a clogged filter will cause major issues, overheating, hard shifts.....key is to be very clean when doing the job....have you ever seen some of the holes in the valve body plate that the fluid runs thru? Some are not much bigger than a pinhead size opening.........you need to make sure that zero dirt is in the pan when you go to put it back on, no speck of pollen that falls out of a tree into the pan, nothing.......you need to make sure there's no excess sealant by new gasket on the inside of the gasket so that when it comes in contact with tranny fluid a tiny piece of sealant doesn't break away and clog something up...... catch 100% of your fluid and funnel it back into an empty quart trans fluid container repeatedly and methodically keep track of EXACTLY how much fluid you removed/need to put back.....when putting pan back on don't overtighten bolts or the gasket will want to squish out the sides , and don't overtighten the bolt that holds the filter on, just nice and snug