hey guys picked up a ek10 a couple months ago on the cheap. It needed quite a bit of TLC which it is currently getting. I have since been able to clean the carb, replace a couple ignition components, replace the gas tank( leaked ), aired up the tires etc etc. I currently have it running driving and mowing very well. I have yet to change the oil in it becuase their is no easy way of doing this from what i can tell. I have done some searching around and came across the service bulletin about a new drain location featured on the 931-01 models which located the drain to be in the sump cover and accessed by a allen shape plug. According to my serial number which is 4261039.....the tra10d engine was manufactured in January of 1966. My thinking is that this was before the addition of the new oil drain location even though I have a 931-01 model. I was able to acquire the original maunals( which have a date of 9/66 on them ) with this machine including a complete list of maintenance that was complete by the owner up until 1975 which is when there is no more info on anything done. The family that owned this was what looked to be a kind that once something stopped working they went out and bought another machine and left the other ones sit. Anyway, is there any really good procedure for changing oil in this thing? The only easy way I can come up with is to siphon the oil out the dip stick tube. Otherwise it looks like the engine has to come out to change it......Also I am starting to think if he did change the oil that he may have changed the trans fluid and not the engine oil lol.....any help is greatly appreciated....