94 940 with 270k miles. The ATF in it isn't burnt but it is black. We've all heard that if u change the fluid in a old car with high miles it will screw the trans up but I think that's just an excuse to cover up neglect. IDK, but if I do it should I just drain and fill or disconnect the line at the radiator, crank it and pour new atf in as the old atf gets pushed out to clean the lines too??

 

the procedure is...

warm up the transmission. pull the main transmission drain plug, let it drain for a good period of time into a clean container. replace the plug and measure how much came out (probably 3-4 quarts), put this much fresh ATF into the tranny dip stick tube via a clean ATF funnel.

now disconnect the upper (return) transmission cooler hose at the radiator, and hook up a vinyl tube of the proper size to the radiator outlet, run that into a clean empty jug that has quantity marks... start the engine, let it idle... for each pint that comes out, add a fresh pint... it will probably take about 4 quarts more added before it runs clear out your vinyl hose.

now button the hose backup, take it for a test drive, and verify the 'hot' level, adding more if needed (but never too much).

 

Change that fluid!

 

Maybe IPD flush hose WITH directions to keep the spilling and mistakes to a minimum....?