Not sure how much I can add, but I'll try. I'm a new-to-me owner of a 2005 T180. I believe the only difference between a 180 and 190 is the mechanics of the lift arms at the rear pivot points. I think the 180 is referred to as a radial lift, and the 190 is ??? So I think everything else is pretty much the same. I haven't yet determined which drive motors I have. One type has an oil reservoir with a drain plug, the svc interval on the oil is 1000 hrs. $45 for 6 ozs from Bobcat. The other drive motor does not have serviceable oil, and I don't know if the oil comes from somewhere else or if its sealed. The local Bobcat technician told me the only way to tell which kind I have is to pull the sprocket and look for the drain bung on the circumference of the hub. There are other threads on this forum that talk about how to drain the oil. Best I can do for now. I don't know about the internal workin's of the the motors, so I don't know how the oil might be seeping out the hole you describe. I saw that mine also had such a hole in the center of the hub, visible even with the sprocket in place. Was it a bear to remove the track and sprocket? I gotta do that to see if my hubs have renewable oil (1100 hrs on the machine now). ---RC