I bought an s60 from a guy who said the only issue was the gearbox was a bit jerky at lower speeds. He attributed it to the MAF sensor. I got it home and checked the trans oil because the guy said he could never find the dipstick. I got it hot and ran it through all the gears and checked the fluid, and it seemed way too high. I checked it a few times to confirm. There is text above the hot line that says "do not overfill' and the fluid is above that ( a little more than halfway up the dipstick).

Is there any chance I just checked it wrong? It is easy to let fluid out of the gearbox? I beleive its a 4 speed, and its a 2.5T

 

The s60 01-07 2.5 has the 5 speed, known to have problems trans. Could be the reason the car was for sale. If would be a good idea to get fresh correct spec fluid in - to be able to evaluate what condition the trans is really in.
Simple multiple drain and fills with the proper fluid will do it - (~3.5 quarts at a time) but if you want something more thorough google "gibbons method".

The correct fluid and the correct level is very important for this trans -