My machine dose not have the oil level bolt on the side of the differential. I had to remove the rear cover to find out how to refill it. Looking at the picture it seems you remove the rubber drain tube at the top and fill it from there.
Thanks for the pic. I guess we now know the two hydros have their differences. You are now the expert on the 3600 tranny, as I haven't even looked at my 6800 as closely. As far as draining it, I have no idea.
We need someone with a service manual for the 3600 to help oout here.