Yee Haw. My children are growing up and licensed so the wife and I bought a used 2010 Honda Civic LX sedan for them. This car is quite basic but will serve our high schoolers needs admirably. That said, to the best of my knowledge, only the motor oil has been changed periodically. So it is time to change the fluids: power steering, auto transmission, brake fluid, and coolant.
Automatic transmission fluid change time at 58,500 miles.
Out: Presumably Honda factory fill of Z-1 fluid. As near as I can tell, 2010 was the final year that Honda used Z-1 trans fluid.
In: Drained and filled four separate times of eight quarts of Honda DW-1 fluid in two quart increments.
I am sure the factory fill was still in the transmission as some gorilla at Honda tightened the drain bolt in excess of 100 foot-pounds. I broke my 3/8" drive ratchet trying to loosen the drain bolt.
Anyhow, the old fluid was a dark red while the magnet on the drain plug was full of black film. I cleaned the magnet as well.
Road testing the Civic really saw no appreciable change in transmission operation. The shift points from 1st to 2nd and 2nd to 3rd may have decreased by all of one mile per hour, but that is debatable.