Firstly get the observations and do the needful as:
Grab the dip stick of transmission oil and run it through your fingers to get them oily. Spread the oil on your fingers and observe:
Transparent, honey-like colour, no visible sediments, nice greasy feeling? You are good to go.
Transparent, dark-brown to black, no sediments? Consider changing the oil soon.
Murky, sediment-y, dark black? Change ASAP.
Or get confused with observations then get it change because in JDM cars mileage is also an issue because of reversing the actual reading by dealers.